Service Discovery using Avi Vantage as IPAM and DNS

Transcription

1 Page 1 of 10

2 Service Discovery using Avi Vantage as IPAM and DNS Provider view online This article walks through the configuration of Avi Vantage's native IPAM and DNS solution for providing service discovery. The Avi Vantage IPAM/DNS solution is available for the following clouds: Containers (Mesos, OpenShift, Kubernetes, Docker UCP, Rancher) Linux server VMware Read Access No access OpenStack Amazon Web Services The Avi Vantage IPAM/DNS profile consists of both IPAM- and DNS-related configuration in a single bundle. It is recommended to have both IPAM and DNS configuration in a single profile for ease of management. However, configuration of one can exclude the other if different profiles for IPAM and DNS are preferred. For example, "vantage-ipam" can be created without configuring any DNS domains and "vantage-dns" can be created without any networks/subnets and only domain names. Note: Prior to the 16.3 release, Avi supported the addition of virtual service FQDNs via service discovery on a DNS server hosted on the Avi Controller. This is deprecated as of release An Avi DNS is implemented on Service Engines instead. Refer to Avi DNS Architecture and Features, especially the configuration section. IPAM Configuration Avi Vantage allocates IP addresses from a pool of IP addresses within the subnet configured as listed below. Note: Navigate to Infrastructure > Clouds, and click on the cloud name. Select Network and click Create. Enter a name for the network. Add networks for IP address allocation: Click Save. Click Add Subnet. Enter the subnet address, in the following format: /24 Click Add Static IP address pool. Avi Vantage will allocate IP addresses from this pool. For example, Click Save. Repeat 1-4 for each network to be used for IP address allocation. Virtual service creation will fail if the static IP address pool is empty or exhausted. For East West IPAM (applicable to container-based clouds, i.e., Mesos, OpenShift, Kubernetes, Docker UCP, and Rancher), create another network with the appropriate link-local subnet and a separate IPAM/DNS Profile. IPAM network creation after following steps 1 through 5 above: Copyright 2018 Avi Networks, Inc. Page 2 of 10

3 East-west IPAM network creation after steps 1 through 5 above: Navigate to Templates -> IPAM/DNS Profile and create a placeholder IPAM profile as shown below. Copyright 2018 Avi Networks, Inc. Page 3 of 10

4 Usable Networks This feature enables assigning one or more of the networks created above to be default usable networks, if no specific network /subnet is provided in the virtual service configuration. An administrator can configure these networks, thus eliminating the need for a developer to provide a specific network/subnet while creating a virtual service for the application. Copyright 2018 Avi Networks, Inc. Page 4 of 10

5 DNS Configuration 1. Navigate to Templates -> IPAM/DNS Profile and create a DNS profile by selecting Avi Vantage DNS in the pulldown menu. Copyright 2018 Avi Networks, Inc. Page 5 of 10

6 2. Add one or more DNS Service Domain names as shown in the below screenshot. Avi Vantage will be the authoritative DNS server for these domains. 3. Configure a TTL value for all records for a particular domain, or leave the Record TTL field blank to accept the default TTL of 300 seconds. 4. Click Save (or Next -> Save). Copyright 2018 Avi Networks, Inc. Page 6 of 10

7 Using Avi Vantage DNS After configuring a DNS profile (above) with a set of domains for which Avi Vantage DNS will be serving records, configure a DNS virtual service in Avi Vantage for applications to discover each other. This serves two purposes, DNS high availability and interoperability with other DNS providers in the same cluster (Mesos-DNS, for example). Setting up DNS virtual service: 1. Create a DNS Pool with back-end servers consisting of all Controller IPs in the cluster, with the server port as 53. Note: If the Controllers are running on Mesos nodes with Mesos DNS enabled, use port Copyright 2018 Avi Networks, Inc. Page 7 of 10

8 2. Create a virtual service with the following attributes: Publicly-accessible virtual IP address. "System-DNS" as the Application Profile. Check "Ignore network reachability constraints for the server pool." If the Controller is on an external network (requires routing for SE data traffic to reach the Controller), then add a static route to the Controller network as shown below. Copyright 2018 Avi Networks, Inc. Page 8 of 10

9 To add a static route (when the Controller is in an external network), navigate to Infrastructure > Routing > Create and add a Default-Gateway IP address for the cluster. 3. There are 2 ways to enable Avi DNS service in your data center. Copyright 2018 Avi Networks, Inc. Page 9 of 10

10 Add DNS VIP (" " as configured above) to the nameservers' list in /etc/resolv.conf on all nodes requiring service discovery. Create applications and verify resolution works for the application's FQDN by issuing "dig app-name. domain" anywhere in the cluster. Add DNS VIP in the corporate DNS server as the nameserver for serving domain names configured in the DNS profile above. Any requests to "mycompany-cloud" will be redirected to and serviced by the Avi DNS service. Copyright 2018 Avi Networks, Inc. Page 10 of 10