Unified Load Balance. User Guide. Issue 04 Date

Transcription

1 Issue 04 Date

2 Contents Contents 1 Overview Basic Concepts Unified Load Balance Listener Health Check Region Project Functions Differences from ELB Related Services Best Practices Web Service Load Balancing Large File Transfer Over TCP Highly Concurrent Access High Performance Getting Started Configuration Description Creating a TCP Private Network Load Balancer Creating an HTTP Public Network Load Balancer Operation Guide Load Balancer Management Listener Management Backend ECS Management FAQs Unified Load Balance Can I Adjust the Bandwidth of a Load Balancer? Which Forwarding Rules Does ULB Support? Does ULB Support ECSs Running Different OSs? How Many Load Balancers Can I Have? How Can I Configure a Public/Private Network Load Balancer? What Functions Do Listeners Provide? What Are Protocols and Frontend Ports? Issue 04 ( ) ii

3 Contents 5.9 What Are ECS Protocols and Ports? Is the EIP Assigned to the ULB Service Used Exclusively? Will There Be Any Adverse Impact If I Delete My Load Balancer? How Do I Rectify a Health Check Failure? Why Cannot the VIP Be Pinged from ULB Backend ECSs in the IP Scenario? Why Do Many IP Addresses Accessing the Backend ECSs of a Load Balancer Begin with ? How Can I Obtain the Real IP Address of a Visitor? What Types of Sticky Sessions Does ULB Support? What Are the Limitations of the ULB IP Mode? How Do I Deploy the Active/Standby VRRP Service? How Do I Configure Cloud-Init in the IP Load Balancing Scenario?...43 A Change History Issue 04 ( ) iii

4 1 Overview 1 Overview 1.1 Basic Concepts Unified Load Balance Listener Unified Load Balance (ULB) is a traffic distribution control service that distributes access traffic to multiple ECSs based on the forwarding policy. ULB enables you to achieve higher levels of fault tolerance in your applications and expand application service capabilities. In addition, ULB supports centralized deployment of internal and external networks and active/standby Virtual Router Redundancy Protocol (VRRP) deployment, and access through the VPN, direct connections, and across VPCs. You can create a load balancer on a web-based console, configure listening ports and backend ECSs required for the service. The service helps to eliminate single points of failure (SPOFs), improving availability of the whole system. You can create a listener and define the load balancing policy and forwarding rule. The followings are some concepts related to the load balancing policy and forwarding rule: The listener specifies the load balancing policy based on the protocol of the connection between the client and load balancer, the protocol of the connection between the load balancer and backend ECSs, and ports. The load balancer supports HTTP, TCP, and IP, and can listen to ports 1 to In the IP scenario, the load balancer listens to port 0. The following three types of forwarding rules are available: Round robin: Each connection request is distributed to the next ECS in sequence so that all requests are distributed evenly to all ECSs. Least connections: New connections are distributed to the ECS processing the least connections. Source IP address: The source IP address of the request sender is used as the HashKey to identify the ECS in the static fragment table. You can choose an appropriate algorithm based on your requirement to distribute access traffic and improve load balancing capabilities. Issue 04 ( ) 1

5 1 Overview Health Check Region Project 1.2 Functions The following three types of sticky session modes are available: SOURCE_IP: The source IP address of the request is used as the HashKey to identify the ECS in the static fragment table. HTTP_COOKIE: The load balancer will generate a cookie after it receives a request from a client. All the subsequent requests with the cookie will be distributed to the same backend server for processing. APP_COOKIE: This method relies on backend applications. Backend applications will generate a cookie and all requests with the cookie will be distributed to the same backend server for processing. You can choose an appropriate algorithm based on your requirement to distribute access traffic and improve load balancing capabilities. You can configure the health check to monitor the status of backend ECSs and ensure that the load balancer forwards requests only to ECSs that are running properly. After an abnormal ECS recovers, it will automatically continue to provide services. The protocols that can be used for the health check include TCP and HTTP. A region is the physical location where ULB is deployed. Each region comprises one or more AZs and is completely isolated from other regions. Only AZs in the same region can communicate with one another through an internal network. Public cloud data centers are deployed worldwide, such as North America, Europe, and Asia. ULB can be deployed in different regions. Enabling ULB in the required region can better suit local users' requirements or comply with local laws and regulations. A project is used to group and isolate OpenStack resources, including computing, storage, and network resources. A project can be a department or a project team. Multiple projects can be created for one account. ULB allows you to control load balancing. A self-service web-based console is provided for you to easily configure the ULB service and quickly add service resources to implement load balancing. ULB provides the following functions: Linear capacity expansion, eliminating SPOFs Support for TCP, IP, and HTTP load balancing The IP mode support UDP, VRRP, and source IP address visibility. Support access by the VPN, internal, and external networks Issue 04 ( ) 2

6 1 Overview 1.3 Differences from ELB 1.4 Related Services ULB is an evolved version of Elastic Load Balance (ELB). It has all functions of ELB and provides extra functions as follows: Development using standard OpenStack APIs Unified deployment of the internal and external networks Service access through the VPN, direct connections, and across VPCs Active/Standby service deployment using VRRP IP (layer-3 network) applications ULB does not support certificate management. For applications without certificate management, ULB is recommended as the preferred load balancing solution. Virtual Private Cloud (VPC) The service requires the elastic IP addresses and subnets assigned in the VPC service. Auto Scaling (AS) After ULB is configured, AS automatically adds or removes ECSs bound to a load balancer in a scaling action. Cloud Trace Service (CTS) ULB operations can be recorded by CTS. Identity and Access Management (IAM) The service requires IAM to provide authentication. Cloud Eye Service (CES) After you have enabled ULB, you can use CES to view status of monitored objects of the service, without requiring additional plug-ins to be installed. Table 1-1 lists the ULB metrics supported by CES. Table 1-1 ULB monitoring metrics Metric cps Active Connections New cps Incoming Packets Description This metric is used to show the number of concurrent connections processed by the monitored object per second (connections/second). This metric is used to show the number of active connections processed by the monitored object per second (connections/second). This metric is used to show the number of new connections processed by the monitored object per second (connections/second). This metric is used to show the number of incoming packets on the monitored object per second (packets/second). Issue 04 ( ) 3

7 1 Overview Metric Inbound Rate Outbound Rate Abnormal Hosts Normal Hosts Description This metric is used to show the number of incoming bytes per second (bytes/second) on the monitored object. This metric is used to show the number of outgoing bytes per second (bytes/second) on the monitored object. This metric is used to show the number of abnormal backend ECSs associated with a load balancer. This metric is used to show the number of normal backend ECSs associated with a load balancer. Issue 04 ( ) 4

8 2 Best Practices 2 Best Practices 2.1 Web Service Load Balancing Overview For web services where users need to register themselves and log in, such as and (two online shopping malls in China), HTTP load balancing is recommended. The client and load balancer can communicate through a direct connection or VPN. Figure 2-1 HTTP load balancing Requirements Web message forwarding over HTTP Cookie sticky session Configuration Key Points A cookie can ensure that requests from the same user are sent to the same server for processing. Without the cookie, the user login may encounter an exception or time out. Balanced distribution of requests Requests from different users are forwarded to different servers for processing. Service fault detection and isolation Faulty servers can be detected quickly and isolated. Configure layer-7 load balancing, that is, select HTTP for Protocol. Select Round robin for LB Algorithm. Select the sticky session type. Select either the TCP or HTTP health check mode. If you select the HTTP check mode, you must ensure that an ECS health check page is available and that 200 is returned when you visit the page. Issue 04 ( ) 5

9 2 Best Practices Configuration Procedure Step 1 Create a load balancer (you can also use a created load balancer if there is any). Choose whether to use an EIP based on site requirements. Before creating a load balancer, you need to create a VPC and plan its use. Figure 2-2 Creating a load balancer Step 2 Add a listener. 1. Select HTTP and configure the port for Protocol/Frontend Port as required. 2. Select Round robin for LB Algorithm. 3. Select HTTP cookie for Sticky Session Type. 4. Select HTTP or TCP for Health Check Mode. 5. The port used for health check must be the same as that used for providing services. Retain default values of other health check configuration items. Issue 04 ( ) 6

10 2 Best Practices Figure 2-3 Adding a listener Step 3 Add backend ECSs. Locate the row that contains the target listener and click Add Backend ECS in the Operation column to add the backend ECSs based on service planning. Figure 2-4 Adding backend ECSs On the Add Backend ECS page, select the subnet and enter the port number. Then select target backend ECSs from the list. You can filter target ECSs by the ECS running status, name, or IP address. Issue 04 ( ) 7

11 2 Best Practices Figure 2-5 Adding backend ECSs Step 4 View backend ECSs Click the Backend ECS tab to view the added backend ECSs. Figure 2-6 Viewing backend ECSs ----End API Calls Step 1 Create a load balancer. 1. Run the following command to obtain the actual subnet through the subnet on the console: neutron net-show subnet_id Issue 04 ( ) 8

12 2 Best Practices Figure 2-7 Obtaining the subnet 2. Run the following command to create a load balancer: neutron lbaas-loadbalancer-create real_subnet_id Figure 2-8 Creating a load balancer Step 2 Add a listener. 1. Run the following command to add a listener: neutron lbaas-listener-create --loadbalancer lb_id --protocol HTTP --protocol-port 80 Figure 2-9 Adding a listener 2. Run the following command to create a pool: neutron lbaas-pool-create --listener listener_id --lb-algorithm ROUND_ROBIN -- session-persistence type=http_cookie --protocol HTTP Figure 2-10 Creating a pool 3. Run the following command to create a healthmonitor: Issue 04 ( ) 9

13 2 Best Practices neutron lbaas-healthmonitor-create --pool pool_id --type HTTP --max-retries 3-- delay 5 --timeout 10 Figure 2-11 Creating a healthmonitor Step 3 Adding a backend ECS neutron lbaas-member-create pool_id --subnet real_subnet_id --address real_server_ip_01 --protocol-port 222 Figure 2-12 Adding a backend ECS ----End 2.2 Large File Transfer Over TCP Overview For the transfer of large files, such as videos, movies, audios, and other ultra-sized files, TCP load balancing is recommended. The client and load balancer can communicate through a direct connection or VPN. Figure 2-13 TCP load balancing Requirements High data transmission reliability Data cannot be lost. Low data transmission delay Data must be transmitted quickly. High data forwarding throughput Service fault detection and isolation Faulty servers can be detected quickly and isolated. Issue 04 ( ) 10

14 2 Best Practices Configuration Key Points Configuration Procedure Configure layer-7 load balancing, that is, select TCP for Protocol. Select Round robin for LB Algorithm. Select the sticky session type. Configure a stickiness duration longer than the service session timeout duration. For example, if the service session timeout duration is 200s, you can set the stickiness duration to 240s. Select the TCP health check mode. Step 1 Create a load balancer (you can also use a created load balancer if there is any). Choose whether to use an EIP based on site requirements. Before creating a load balancer, you need to create a VPC and plan its use. Figure 2-14 Creating a load balancer Step 2 Add a listener. 1. Select TCP and configure the port for Protocol/Frontend Port as required. 2. Select Round robin for LB Algorithm. 3. Select HTTP cookie for Sticky Session Type. 4. Select TCP for Heath Check Mode. 5. The port used for health check must be the same as that used for providing services. Issue 04 ( ) 11

15 2 Best Practices Figure 2-15 Adding a listener Step 3 Add backend ECSs. Locate the row that contains the target listener and click Add Backend ECS in the Operation column to add the backend ECSs based on service planning. Figure 2-16 Adding backend ECSs On the Add Backend ECS page, select the subnet and enter the port number. Then select target backend ECSs from the list. You can filter target ECSs by the ECS running status, name, or IP address. Issue 04 ( ) 12

16 2 Best Practices Figure 2-17 Adding backend ECSs Step 4 View backend ECSs Click the Backend ECS tab to view the added backend ECSs. Figure 2-18 Viewing backend ECSs ----End API Calls Step 1 Create a load balancer. 1. Run the following command to obtain the actual subnet through the subnet on the console: neutron net-show subnet_id Issue 04 ( ) 13

17 2 Best Practices Figure 2-19 Obtaining the subnet 2. Run the following command to create a load balancer: neutron lbaas-loadbalancer-create real_subnet_id Figure 2-20 Creating a load balancer Step 2 Add a listener. 1. Run the following command to add a listener: neutron lbaas-listener-create --loadbalancer lb_id --protocol TCP --protocol-port 80 Figure 2-21 Adding a listener 2. Run the following command to create a pool: neutron lbaas-pool-create --listener listener_id --lb-algorithm ROUND_ROBIN -- session-persistence type=http_cookie --protocol TCP Figure 2-22 Creating a pool 3. Run the following command to create a healthmonitor: neutron lbaas-healthmonitor-create --pool pool_id --type TCP --max-retries 3 -- delay 5 --timeout 10 Issue 04 ( ) 14

18 2 Best Practices Figure 2-23 Creating a healthmonitor Step 3 Add a backend ECS. neutron lbaas-member-create pool_id --subnet real_subnet_id --address real_server_ip_01 --protocol-port 111 Figure 2-24 Adding a backend ECS ----End 2.3 Highly Concurrent Access Overview For the high concurrent access by Internet users or persistent connection to the database, TCP load balancing is recommended. The client and load balancer can communicate through a direct connection or VPN. Figure 2-25 TCP load balancing Requirements Configuration Key Points Over one million concurrent access Persistent service connection and stable data forwarding Balanced data forwarding and distribution of connections and requests Service fault detection and isolation Configure layer-7 load balancing (select TCP for Protocol). Select the least connections algorithm. In the persistent connection scenario, the least connections algorithm is superior, followed by the polling algorithm. Disable sticky session. Select the TCP health check mode. Issue 04 ( ) 15

19 2 Best Practices Configuration Procedure Faulty servers can be detected quickly and isolated. Step 1 Create a load balancer (you can also use a created load balancer if there is any). Choose whether to use an EIP based on site requirements. Before creating a load balancer, you need to create a VPC and plan its use. Figure 2-26 Creating a load balancer Step 2 Add a listener. 1. Select TCP and configure the port for Protocol/Frontend Port as required. 2. Select the least connections algorithm. 3. Disable sticky session. 4. Select TCP for Heath Check Mode. 5. The port used for health check must be the same as that used for providing services. Issue 04 ( ) 16

20 2 Best Practices Figure 2-27 Adding a listener Step 3 Add backend ECSs. Locate the row that contains the target listener and click Add Backend ECS in the Operation column to add the backend ECSs based on service planning. Figure 2-28 Adding backend ECSs On the Add Backend ECS page, select the subnet and enter the port number. Then select target backend ECSs from the list. You can filter target ECSs by the ECS running status, name, or IP address. Issue 04 ( ) 17

21 2 Best Practices Figure 2-29 Adding backend ECSs Step 4 View backend ECSs Click the Backend ECS tab to view the added backend ECSs. Figure 2-30 Viewing backend ECSs ----End API Calls Step 1 Create a load balancer. 1. Run the following command to obtain the actual subnet through the subnet on the console: neutron net-show subnet_id Issue 04 ( ) 18

22 2 Best Practices Figure 2-31 Obtaining the subnet 2. Run the following command to create a load balancer: neutron lbaas-loadbalancer-create real_subnet_id Figure 2-32 Creating a load balancer Step 2 Add a listener. 1. Run the following command to add a listener: neutron lbaas-listener-create --loadbalancer lb_id --protocol HTTP --protocol-port 80 Figure 2-33 Adding a listener 2. Run the following command to create a pool: neutron lbaas-pool-create --listener listener_id --lb-algorithm LEAST_CONNECTIONS --protocol TCP Figure 2-34 Creating a pool 3. Run the following command to create a healthmonitor: Issue 04 ( ) 19

23 2 Best Practices neutron lbaas-healthmonitor-create --pool pool_id --type TCP --max-retries 3 -- delay 5 --timeout 10 Figure 2-35 Creating a healthmonitor Step 3 Add a backend ECS. neutron lbaas-member-create pool_id --subnet real_subnet_id --address real_server_ip_01 --protocol-port 111 Figure 2-36 Adding a backend ECS ----End 2.4 High Performance Overview In high performance or cross-vpc access scenarios, you can choose the DR mode which is based on IP (including UDP and TCP). In this mode, the source IP address is visible and no port number is required. Backend ECSs directly return response messages to the client, without requiring the load balancer to forward these messages. The client and load balancer can communicate through a direct connection, VPN, or VPC peering. Figure 2-37 Load balancing based on IP addresses Requirements High performance Balanced data forwarding and distribution of connections and requests Service fault detection and isolation Faulty servers can be detected quickly and isolated. Issue 04 ( ) 20

24 2 Best Practices Configuration Key Points Configuration Procedure Configure the DR mode. The port number is not required and the load balancer cannot have other listeners. Select the TCP health check mode. Step 1 Create a load balancer (you can also use a created load balancer if there is any). Choose whether to use an EIP based on site requirements. Before creating a load balancer, you need to create a VPC and plan its use. Figure 2-38 Creating a load balancer Step 2 Add a listener. 1. Select the TCP health check mode. 2. Select a load balancing algorithm as required. 3. Select TCP for Heath Check Mode. 4. The port used for health check must be the same as that used for providing services. Issue 04 ( ) 21

25 2 Best Practices Figure 2-39 Adding a listener Step 3 Add backend ECSs. Locate the row that contains the target listener, click Add Backend ECS in the Operation column. Add the backend ECSs associated with the load balancer based on service planning. Figure 2-40 Adding backend ECSs On the Add Backend ECS page, select the subnet and enter the port number. Then select target backend ECSs from the list. You can filter target ECSs through the ECS running status, name, or IP address. Issue 04 ( ) 22

26 2 Best Practices Figure 2-41 Adding backend ECSs Step 4 View backend ECSs Click the Backend ECS tab to view the added backend ECSs. Figure 2-42 Viewing backend ECSs ----End API Calls Step 1 Create a load balancer. 1. Run the following command to obtain the actual subnet through the subnet on the console: neutron net-show subnet_id Issue 04 ( ) 23

27 2 Best Practices Figure 2-43 Obtaining the subnet 2. Run the following command to create a load balancer: neutron lbaas-loadbalancer-create real_subnet_id Figure 2-44 Creating a load balancer Step 2 Add a listener. 1. Run the following command to add a listener: neutron lbaas-listener-create --loadbalancer lb_id --protocol TCP --protocol-port 0 Figure 2-45 Adding a listener 2. Run the following command to create a pool: neutron lbaas-pool-create --listener listener_id --lb-algorithm SOURCE_IP -- protocol TCP Figure 2-46 Creating a pool 3. Run the following command to create a healthmonitor: neutron lbaas-healthmonitor-create --pool pool_id --type TCP --max-retries 3--delay 5 --timeout 10 Issue 04 ( ) 24

28 2 Best Practices Figure 2-47 Creating a healthmonitor Step 3 Add a backend ECS. neutron lbaas-member-create pool_id --subnet real_subnet_id --address real_server_ip_01 --protocol-port 111 Figure 2-48 Adding a backend ECS ----End Issue 04 ( ) 25

29 3 Getting Started 3 Getting Started 3.1 Configuration Description To use the service to distribute traffic to multiple backend ECSs, you need to create a load balancer, add a listener to the load balancer, configure the health check, and add backend ECSs to the listener. If you want to provide the load balancing service for public network users and distribute access traffic from the Internet to multiple backend ECSs, bind an elastic IP address to the load balancer. For details, see section 3.3 Creating an HTTP Public Network Load Balancer. If you want to provide the load balancing service for private network users and distribute access traffic in the same VPC to multiple backend ECSs, you do not need to bind an elastic IP address to the load balancer. For details, see section 3.2 Creating a TCP Private Network Load Balancer. Figure 3-1 shows the configuration process Issue 04 ( ) 26

30 3 Getting Started Figure 3-1 Configuration process 3.2 Creating a TCP Private Network Load Balancer Scenarios Prerequisites This section describes how to create a private network load balancer on the management console. The created load balancer can receive and forward TCP requests to backend ECSs in the same VPC. ECSs to be added to the load balancer have been started and can be accessed through port 22 by other ECSs in the same security group using TCP. Create a Private Network Load Balancer To create a private network load balancer, perform the following operations: 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. Issue 04 ( ) 27

31 3 Getting Started Add a Listener Add Backend ECSs 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click Create Load Balancer. 6. On the Create Load Balancer page, configure parameters listed in Table Click Create Now. 8. Confirm the configuration and click Submit. 9. After you submit the task, close the page. Perform the following operations to configure a listener that receives TCP requests from port 22 and forwards these requests to backend ECSs, and to configure the health check for the load balancer: 1. On the displayed page, select the target load balancer for which a listener is to be added. 2. Click the name of the target load balancer. 3. In the Listener area, click Add Listener. 4. In the displayed dialog box, configure the listener based on Table 4-2. Set Protocol/ Frontend Port to TCP/ Click Next. Perform the following operations to add backend ECSs to the listener so that the listener can distribute traffic to ECSs: 1. On the displayed page, select the target load balancer for which backend ECSs are to be added. 2. Click the name of the target load balancer. 3. In the Listener area, select the target listener. 4. Click Add Backend ECS in the Operation column. 5. On the displayed page, select the subnet, enter the backend port, and select backend ECSs to be added. For more information about the parameters, see Table 4-4. You can filter backend ECSs by their running status, name, and private IP address. 6. Click OK. 3.3 Creating an HTTP Public Network Load Balancer Scenarios This section describes how to create a public network load balancer using an EIP on the management console. The created load balancer can forward HTTP requests from the public network to backend ECSs. Issue 04 ( ) 28

32 3 Getting Started Prerequisites ECSs to be added to the load balancer have been started and security rules of the ECSs allow access through port 80 using HTTP. Create a Public Network Load Balancer Add a Listener Add Backend ECSs To create a load balancer with an EIP, perform the following operations: 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click Create Load Balancer. 6. On the Create Load Balancer page, configure parameters listed in Table Click Create Now. 8. Confirm the configuration and click Submit. 9. After you submit the task, close the page. Perform the following operations to add a listener that receives HTTP requests from port 80 and forwards these requests to backend ECSs, and to configure the health check for the load balancer. 1. On the displayed page, select the target load balancer for which a listener is to be added. 2. Click the name of the target load balancer. 3. In the Listener area, click Add Listener. 4. In the displayed dialog box, configure the listener based on Table 4-2. Set Protocol/ Frontend Port to HTTP/ Click Next. Perform the following operations to add backend ECSs to your load balancer so that the load balancer can distribute traffic to ECSs: 1. On the displayed page, select the target load balancer for which backend ECSs are to be added. 2. Click the name of the target load balancer. 3. In the Listener area, select the target listener. 4. Click Add Backend ECS in the Operation column. 5. On the displayed page, select the subnet, enter the backend port, and select backend ECSs to be added. For more information about the parameters, see Table 4-4. You can filter backend ECSs by their running status, name, and private IP address. 6. Click OK. Issue 04 ( ) 29

33 4 Operation Guide 4 Operation Guide 4.1 Load Balancer Management This section describes how to create, query, or delete a load balancer. If you want to create a load balancer, view details of a load balancer, and delete a load balancer that is no longer in use, you can refer to this section. Create a Load Balancer To create a load balancer with an EIP, perform the following operations: 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click Create Load Balancer. 6. On the Create Load Balancer page, configure parameters listed in Table 4-1. Table 4-1 Parameter description Parameter Description Example Value Name Specifies the load balancer name. ULB-93wd VPC Subnet Specifies the VPC to which the load balancer belongs. You can select an existing VPC, or click View VPC and create a desired one. For more information about VPC, see the Virtual Private Cloud User Guide. Specifies the subnet to which the load balancer belongs. vpc-4536 subnet-4536 Issue 04 ( ) 30

34 4 Operation Guide Parameter Description Example Value LB Virtual IP Address EIP Description Specifies the IP address of the load balancer. You can set it to Automatic assignment or Manual assignment. If you set it to Manual assignment, enter an IP address. Specifies the IP address bound to the load balancer and enabling the load balancer to receive and automatically forward access requests from the public network to multiple ECSs. The following options are available: Do Not Use: The load balancer cannot receive requests from the public network. Use Existing EIP: An existing EIP will be used to create the load balancer. You need to select an existing EIP. Provides description of the load balancer Use Existing EIP - Query a Load Balancer 7. Click Create Now. 8. Confirm the configuration and click Submit. 9. After you submit the task, close the page. You can query the status and subnet of a created load balancer on the Unified Load Balance page. 1. From the drop-down list at the upper right corner of the load balancer list, select the name, public IP address, or subnet to query a load balancer. 2. Click the name of a load balancer to query its details. Bind an EIP to a Load Balancer Bind an EIP to a load balancer to enable the load balancer to receive requests from the public network. 1. On the load balancer list, click the name of a load balancer to enter the details page. 2. Click Bind following EIP and select the EIP to be bound from the drop-down list. 3. Click to bind the EIP to the load balancer. 4. To unbind the IP address, click Unbind. Issue 04 ( ) 31

35 4 Operation Guide Delete a Load Balancer If you do not use a load balancer any longer, you can delete it. 1. On the Unified Load Balance page of the management console, locate the row that contains the target load balancer and click Delete. 2. In the dialog box displayed, click OK. NOTE If the load balancer has listeners, delete the listeners first before deleting the load balancer. 4.2 Listener Management Scenarios Add a Listener A listener is a process that checks for connection requests. It is configured with a protocol and port number for connections from clients to the load balancer and a protocol and port number for connections from the load balancer to backend ECSs. The listener automatically checks status of all backend ECSs. If a backend ECS is not running properly, the load balancer will stop forwarding traffic to the ECS. This section describes how to add, modify, and delete a listener. If you want to add a listener to a load balancer, change the load balance mode of a listener, sticky session type, or health check configuration, or do not want to use a listener, you can refer to this section. 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click the name of the target load balancer. 6. In the Listener area of the Summary page, click Add Listener. Configure the parameters according to Table 4-2. Table 4-2 Parameter description Parameter Description Example Value Name Specifies the name of the listener. listener01 Issue 04 ( ) 32

36 4 Operation Guide Parameter Description Example Value Protocol/Frontend Port LB Algorithm Specifies the load distribution protocol and port. The port value ranges from 1 to and the following protocols are available: HTTP: layer-7 load balancing TCP: layer-4 load balancing IP: IP-based (including UDP and TCP) load balancing with the source IP address visible and no port number required IP load balancing is also called the DR mode, which has the best load balancing performance. The request result is returned by the server providing the service to the client. Specifies the algorithm that the load balance uses. Round robin: Each connection request is distributed to the next ECS in sequence so that all requests are distributed evenly to all ECSs. Least connections: New connections are distributed to the ECS processing the least connections. Source IP address: The source IP address of the request sender is used as the HashKey to identify the ECS in the static fragment table. NOTE You can choose an appropriate algorithm based on your requirement to distribute access traffic and improve load balancing capabilities. HTTP/80 Round robin Issue 04 ( ) 33

37 4 Operation Guide Parameter Description Example Value Sticky Session Type Description Health Check Mode Interval (s) Timeout (s) Check Path Maximum Retries Specifies the sticky session type. Source IP address: The source IP address of the request sender is used as the HashKey to identify the ECS in the static fragment table. HTTP cookie: The load balancer will generate a cookie after it receives a request from a client. All the subsequent requests with the cookie will be distributed to the same backend server for processing. App cookie: This method relies on backend applications. Backend applications will generate a cookie and all requests with the cookie will be distributed to the same backend server for processing. NOTE The source IP address type applies to TCP and IP. You can choose an appropriate algorithm based on your requirement to distribute access traffic and improve load balancing capabilities. Provides supplementary information about the listener. Specifies the supported health check mode. Four values are available (the value cannot be modified once it is set): PING: available only when Protocol is set to IP HTTPS: available only when Protocol is set to TCP. TCP: available when Protocol is set to HTTP, IP, or TCP HTTP: available only when Protocol is set to TCP or HTTP. Specifies the maximum interval for the health check. Specifies the maximum timeout duration for the health check. Specifies the health check path (a URL). This parameter is required if Health Check Mode is set to HTTP. Specifies the maximum number of retries for the health check. The value ranges from 1 to 10. HTTP_COO KIE None HTTP 5 10 /index.html 3 Issue 04 ( ) 34

38 4 Operation Guide Parameter Description Example Value HTTP Method HTTP Status Code Specifies the HTTP or HTTPS request method. This parameter is required if Health Check Mode is set to HTTP or HTTPS. Specifies the returned status code for an HTTP or HTTPS request. This parameter is required if Health Check Mode is set to HTTP or HTTPS. GET 201 Modify Listener 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click the name of the target load balancer. 6. In the Listener area of the Summary page, click Modify. 7. On the Modify Listener page, set parameters as prompted. Table 4-3 Parameter description Parameter Description Example Value Name Specifies the name of the listener. listener01 LB Algorithm Specifies the algorithm that the load balance uses. Round robin: Each connection request is distributed to the next ECS in sequence so that all requests are distributed evenly to all ECSs. Least connections: New connections are distributed to the ECS processing the least connections. Source IP address: The source IP address of the request sender is used as the HashKey to identify the ECS in the static fragment table. NOTE You can choose an appropriate algorithm based on your requirement to distribute access traffic and improve load balancing capabilities. Round robin Issue 04 ( ) 35

39 4 Operation Guide Parameter Description Example Value Sticky Session Type Description Health Check Mode Interval (s) Timeout (s) Check Path Maximum Retries Specifies the sticky session type. Source IP address: The source IP address of the request is used as the HashKey to identify the ECS in the static fragment table. HTTP cookie: The load balancer will generate a cookie after it receives a request from a client. All the subsequent requests with the cookie will be distributed to the same backend server for processing. App cookie: This method relies on backend applications. Backend applications will generate a cookie and all requests with the cookie will be distributed to the same backend server for processing. NOTE The source IP address type applies to TCP and IP. You can choose an appropriate algorithm based on your requirement to distribute access traffic and improve load balancing capabilities. Provides supplementary information about the listener. Specifies the health check mode. The following modes are available: PING HTTPS TCP HTTP The value cannot be changed. Specifies the maximum interval for the health check. Specifies the maximum timeout duration for the health check. Specifies the health check path (a URL). This parameter is required if Health Check Mode is set to HTTP. Specifies the maximum number of retries for the health check. The value ranges from 1 to 10. HTTP_COO KIE None None 5 10 /index.html 3 Issue 04 ( ) 36

40 4 Operation Guide Parameter Description Example Value HTTP Method HTTP Status Code Specifies the HTTP or HTTPS request method. This parameter is required if Health Check Mode is set to HTTP or HTTPS. Specifies the returned status code for an HTTP or HTTPS request. This parameter is required if Health Check Mode is set to HTTP or HTTPS. GET 201 Delete a Listener 8. Click OK. 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click the name of the target load balancer. 6. In the Listener area, locate the row of the target listener and click Delete. 7. In the dialog box displayed, click OK. NOTE If backend ECSs have been added to a listener, remove the backend ECSs before deleting the listener. 4.3 Backend ECS Management Scenarios Add Backend ECSs This section describes how to add and remove backend ECSs. If you want to add ECSs to or remove ECSs from a load balancer, you can refer to this section. Before adding a backend ECS, check whether the rule of the security group to which the ECS belongs allows access by /16 and specify the protocol and port that ULB uses for health check. If the protocol and port are not specified, the health check cannot be conducted for the added backend ECS. To query the protocol and port for the health check, select the listener for which the backend ECS is to be added, and click View under Health Check. To configure the security group rule, choose Network > Virtual Private Cloud > Security Group. Locate the security group of the target ECS on the Security Group page and click the security group name to query the rule. 1. Log in to the management console. 2. Click in the upper left corner and select the desired region and project. Issue 04 ( ) 37

41 4 Operation Guide 3. Under Network, click Elastic Load Balance. 4. In the navigation tree on the left, choose Unified Load Balance. 5. On the displayed page, click the name of the target load balancer. 6. Locate the row that contains the target listener and click Add Backend ECS in the Operation column. 7. On the displayed page, select the subnet, enter the backend port, and select backend ECSs to be added. For more information about the parameters, see Table 4-4. You can filter backend ECSs by their running status, name, and private IP address. 8. Click OK. Table 4-4 Parameter description Parameter Description Example Value Backend Port Weight Specifies the port for listening to backend ECSs. The value ranges from 1 to Specifies the weight of a backend ECS. The weight determines the proportion of the number of requests a backend ECS processes. For example, a backend ECS whose weight is 2 processes twice the number of requests processed by a backend ECS whose weight is 1. The default value is Remove Backend ECSs 1. On the load balancer page, click the Backend ECS tab. 2. To remove a single ECS, locate the row that contains the target ECS and click Remove. To remove multiple backend ECSs, select the target ECSs and click Remove above the ECS list. 3. In the dialog box displayed, click OK. Issue 04 ( ) 38

42 5 FAQs 5 FAQs 5.1 Unified Load Balance Unified Load Balance (ULB) is a traffic distribution control service that distributes access traffic to multiple ECSs based on the forwarding policy. ULB enables you to achieve higher levels of fault tolerance in your applications and expand application service capabilities. In addition, ULB supports centralized deployment of internal and external networks and active/standby Virtual Router Redundancy Protocol (VRRP) deployment, and access through the VPN, direct connections, and across VPCs. You can create a load balancer on a web-based console, configure listening ports and backend ECSs required for the service. The service helps to eliminate single points of failure (SPOFs), improving availability of the whole system. 5.2 Can I Adjust the Bandwidth of a Load Balancer? You can adjust the bandwidth of a public network load balancer by adjusting that of the EIP bound to it. For details about how to change the EIP bandwidth, see the Virtual Private Cloud. 5.3 Which Forwarding Rules Does ULB Support? ULB supports the following forwarding rules: Round robin: sends requests to backend ECSs in polling mode. This forwarding rule applies to short-connection services, such as the HTTP service. Least connections: preferentially sends requests to the backend ECS with the least connections. This forwarding rule applies to long-connection services, such as the database service. Source IP address algorithm: calculates the hash value of the request source IP address and sends requests to a matched ECS. This forwarding rule ensures that requests initiated from the same source IP addresses are sent to a fixed ECS. This rule applies to TCP connections of load balancers that do not use cookies. Issue 04 ( ) 39

43 5 FAQs 5.4 Does ULB Support ECSs Running Different OSs? The service has no requirements for the OSs used on backend ECSs. ULB will run properly if your ECSs have consistent data and the same applications deployed. Although there are no specific requirements for backend OSs, it is recommended that you install the same OS on all of your ECSs to simplify operation and maintenance (O&M). If the IP mode is used, only backend ECSs running Linux are supported. 5.5 How Many Load Balancers Can I Have? You can have a maximum of 10 load balancers by default. If you need more load balancers, you can apply for a higher quota. You can apply for a maximum of 255 load balancers. 5.6 How Can I Configure a Public/Private Network Load Balancer? When you create a load balancer, a VIP will be assigned and a private network load balancer is created by default. If you bind a public network IP address to the load balancer, it can serve as a public network load balancer. ULB supports private and public network access simultaneously. 5.7 What Functions Do Listeners Provide? Listeners provide the following functions: ULB protocol and port configuration ECS protocol and port configuration Listening policy configuration 5.8 What Are Protocols and Frontend Ports? The system supports load balancing using IP, TCP (layer 4) or HTTP (layer 7). The system can select a protocol and default port based on the service provided. Protocol IP TCP Function Transparent mode of the IP protocol, which supports the following scenarios: Source IP address transparent transmission UDP service Active/Standby VRRP networking Application deployment using TCP Issue 04 ( ) 40

44 5 FAQs Protocol HTTP Function Web application 5.9 What Are ECS Protocols and Ports? Backend ECSs provide network service protocols and ports. For example, if Internet Information Services (IIS) is installed on a Windows ECS, the default protocol is HTTP, and the default port is Is the EIP Assigned to the ULB Service Used Exclusively? During the life cycle of your ULB service, the assigned EIP is exclusively used by your ULB Will There Be Any Adverse Impact If I Delete My Load Balancer? If your ULB service IP address has been correctly resolved to the domain name and the ULB service runs properly, do not delete your load balancer unless necessary. If the load balancer is deleted, its IP address and service configuration will be released, and deleted data cannot be restored. If you create a load balancer again, a new IP address will be assigned. You can also specify the original IP address when creating the load balancer How Do I Rectify a Health Check Failure? The ULB health check is implemented by detecting the heartbeat communication between the load balancer and backend ECSs. The load balancer communicates with backend ECSs over an intranet. Therefore, to conduct a successful health check, you need to ensure that your ECSs are routable from the intranet. You can perform the following steps to rectify a health check failure. 1. In the Listener area, locate the row that contains the listener for which the health check fails, and click View in the Health Check column. A dialog box is displayed. Check Check Mode: Ensure that the protocol has been configured and port has been enabled for the ECS to be checked. Check Check Path: If HTTP is used for the health check, check whether the health check path for the ECS is correct. 2. Ensure that software, such as the firewall, in the ECS, does not block the health check source IP addresses. 3. Check whether rules of the security group to which the backend ECS belongs allows access by /16, and configure the protocol and port used for the health check of the load balancer. Obtain the health check protocol and port from the dialog box displayed in step If the health check failure persists, contact technical support. Issue 04 ( ) 41

45 5 FAQs 5.13 Why Cannot the VIP Be Pinged from ULB Backend ECSs in the IP Scenario? This is caused by the mechanism of the ULB IP mode. Layer-3 (TCP) load balancing does not allow an ECS added to the backend ECS pool to serve as both a real server and a client to send requests to the load balancer. Returned data packets are sent only among ECSs and not to the load balancer. Therefore, ECSs associated with a load balancer cannot access the VIP Why Do Many IP Addresses Accessing the Backend ECSs of a Load Balancer Begin with ? This issue is caused by the health check of the ULB service. In addition to forwarding external access requests to the backend ECSs using the internal IP addresses of ULB system servers, the ULB service performs health check for the ECSs to check backend service availability. When forwarding external access requests or initiating health check requests, the ULB system translates their source IP addresses into IP addresses starting with , such as /16. To make your external services available, ensure that the security group containing the ECSs allows traffic from these IP addresses How Can I Obtain the Real IP Address of a Visitor? Layer-7 (HTTPS) load balancing automatically obtains real IP addresses of visitors using Http Header:X-Forwarded-For. This function cannot be disabled. Layer-4 (TCP) load balancing requires the TOA plug-in to obtain real IP addresses What Types of Sticky Sessions Does ULB Support? Three types of sticky session are supported: SOURCE_IP, HTTP_COOKIE, and APP_COOKIE What Are the Limitations of the ULB IP Mode? The port number of the listener must be the same as that of the backend ECSs. In the IP mode, VIP must be bound to backend ECSs manually, automatically using Cloud-Init, or using Keepalived in the VRRP active/standby scenarios How Do I Deploy the Active/Standby VRRP Service? For VPN, direct connection, cross-vpc, and Internet access, to deploy the VRRP service by configuring Keepalived on the ECSs, use the VRRP IP address to create a load balancer. Issue 04 ( ) 42

46 5 FAQs 5.19 How Do I Configure Cloud-Init in the IP Load Balancing Scenario? You can use the function provided by Cloud-Init to complete the initial configuration of ECSs. NOTE This method also applies to ECS adding in Auto Scaling (AS). Only ECSs running Linux can be configured using this method. The following is an example command to inject user data (assuming that the VIP is ): #cloud-config bootcmd: - ip addr add /32 dev lo - echo "1" > /proc/sys/net/ipv4/conf/all/arp_ignore - echo "1" > /proc/sys/net/ipv4/conf/lo/arp_ignore - echo "2" > /proc/sys/net/ipv4/conf/lo/arp_announce - echo "2" > /proc/sys/net/ipv4/conf/all/arp_announce is the service IP address of ULB, and it uses the 32-bit mask. Issue 04 ( ) 43

47 A Change History A Change History Release Date What's New This issue is the fourth official release, which incorporates the following change: Added section 2 Best Practices This issue is the third official release, which incorporates the following changes: Added the concepts of region and project. Added operations for selecting a region and project This issue is the second official release, which incorporates the following change: Changed the DR protocol to IP protocol This issue is the first official release. Issue 04 ( ) 44