Critical Analysis and last hour guide for RHCSA/RHCE Enterprise 7

Transcription

1 Critical Analysis and last hour guide for RHCSA/RHCE Enterprise 7 Disclaimer: I haven t gone through RHCSA/RHCE EL 7. I am preparing for upgrade of my RHCE certificate from RHCE EL4 to RHCE EL7. I don t think, I am breaking down non discloser agreement of RHCE as I haven t gone through exam of EL 7. Next, regarding RHCE EL 4, I don t remember any question which I did 8 years back. Similarly, exam pattern and exam objectives are changed by more than 50%, so there is almost not link between RHCE EL4 and RHCE EL7. I have discussed important topics in each section below categorized based on objectives of RHCSA/RHCE, which Red Hat published in Red. Note: RHCE focuses on the useable of the knowledge gained in this course in in our professional life so based on my professional and teaching experience, I am going to highlight important topics in each section, which Red Hat points out. RHCSA Understand and use essential tools Access a shell prompt and issue commands with correct syntax Use input-output redirection (>, >>,, 2>, etc.) Use grep and regular expressions to analyze text Access remote systems using ssh Log in and switch users in multiuser targets Archive, compress, unpack, and uncompress files using tar, star, gzip, and bzip2 Create and edit text files Create, delete, copy, and move files and directories Create hard and soft links List, set, and change standard ugo/rwx permissions Locate, read, and use system documentation including man, info, and files in /usr/share/doc grep command: is very important in our data to data Linux system admin tasks so, we can expect a question related to this command. Input-output redirection: is also important you may need to use in exam.

2 tar command: tar command is also an important archiving command which we use on daily basis, so it is also an important command for archiving. File permission: In case of user management and shared folder for collaboration you can expect it. Operate running systems Boot, reboot, and shut down a system normally Boot systems into different targets manually Interrupt the boot process in order to gain access to a system Identify CPU/memory intensive processes, adjust process priority with renice, and kill processes Locate and interpret system log files and journals Access a virtual machine's console Start and stop virtual machines Start, stop, and check the status of network services Securely transfer files between systems Virtual machine: we are moving to virtualization and cloud, so virtualization in an important topic, so you should be aware of it, Also you should also be able to auto start virtual machines on boot of host (physical) machine. Interrupting the boot process: You should be able to interrupt boot process so that you can find out booting issue like issue in fstab file. Similarly, you should also be familiar on how to recover root password. Locate and interpret system log files and journals: You may not require to directly attempt this section, however, you should be good enough in this section to troubleshoot issues in different application. It will make troubleshoot easy. Process monitoring: you may require to write bash script to retrieve some process related information, so it is also a moderately important topics. Configure local storage List, create, delete partitions on MBR and GPT disks Create and remove physical volumes, assign physical volumes to volume groups, and create and delete logical volumes Configure systems to mount file systems at boot by Universally Unique ID (UUID) or label Add new partitions and logical volumes, and swap to a system non-destructively

3 fdisk: partitioning is one of the most important tasks of system administration, so you should be perfect to create/delete/list partition. fdisk is an easy to use command. Similarly you should be able to create and mount/unmount ext4 and xfs file systems (in next section) as well. UUID: you should be familiar with UUID as by default system mounts drive with UUID LVM: It is one of the most important dynamic disk management technique use in Linux on daily basis. You should be able to create/remove/expand physical volume/ volume group and logical volume. Expanding is an essential task of system admin, so it is an important topic for RHCSA exam. Create and configure file systems Create, mount, unmount, and use vfat, ext4, and xfs file systems Mount and unmount CIFS and NFS network file systems Extend existing logical volumes Create and configure set-gid directories for collaboration Create and manage Access Control Lists (ACLs) Diagnose and correct file permission problems Extend existing logical volumes: it is one to the important task a Linux system admin does. So it is an important topic for RHCE exam. Set-GID: it is very important task when a common folder is shared between different users in same group. So it is important for RHCSA as well. Create and manage ACLs: no doubt file ACLs give additional control to share file/folder. So it is an important topic. Deploy, configure, and maintain systems Configure networking and hostname resolution statically or dynamically Schedule tasks using at and cron Start and stop services and configure services to start automatically at boot Configure systems to boot into a specific target automatically Install Red Hat Enterprise Linux automatically using Kickstart Configure a physical machine to host virtual guests Install Red Hat Enterprise Linux systems as virtual guests Configure systems to launch virtual machines at boot Configure network services to start automatically at boot Configure a system to use time services Install and update software packages from Red Hat Network, a remote repository, or from the local file system

4 Update the kernel package appropriately to ensure a bootable system Modify the system bootloader Network configuration and hostname: network configuration and hostname is the base, without which you will not be able to start working with network. So it is vital. Time service: it is also an important task which as system admin has to be whenever new server is configured. So it is an important task that may also be include in RHCSA exam. o: yum command is an important command to install software, so it is an important topic you should be perfect on this topic, without yum you will not be able install any software. Kernel upgrade: system admin has to update kernel on timely basis to improve performance and security. So no doubt kernel upgrade is a critical task so you should be able to upgrade it. Manage users and groups Create, delete, and modify local user accounts Change passwords and adjust password aging for local user accounts Create, delete, and modify local groups and group memberships Configure a system to use an existing authentication service for user and group information Create/modify/delete user: user administration is an essential task so you should be able to do create/modify/delete user. More importantly you should be able to manage users/group and folder for group collaboration. External authentication: you should be able to authenticate users from external sources like LDAP and Kerberos. In large production system it is defector setting. So it is an important tasks that may be included in RHCE exam. Manage security Configure firewall settings using firewall-config, firewall-cmd, or iptables Configure key-based authentication for SSH Set enforcing and permissive modes for SELinux List and identify SELinux file and process context Restore default file contexts Use boolean settings to modify system SELinux settings

5 Diagnose and address routine SELinux policy violations Key based authentication: for improving key security key based authentication plays an important role. So you may need to configure key based SSH authentication. But, I think it is moderately important for RHCSA exam. SE Linux: you should enable selinux in enforcing mode, so at least you should be able to configure default file contexts for RHCSA. SEbool : may not be important for RHCSA, but is required for RHCE exam.

6 RHCE In preparation System configuration and management Use network teaming or bonding to configure aggregated network links between two Red Hat Enterprise Linux systems Configure IPv6 addresses and perform basic IPv6 troubleshooting Route IP traffic and create static routes Use firewalld and associated mechanisms such as rich rules, zones and custom rules, to implement packet filtering and configure network address translation (NAT) Use /proc/sys and sysctl to modify and set kernel runtime parameters Configure a system to authenticate using Kerberos Configure a system as either an iscsi target or initiator that persistently mounts an iscsi target Produce and deliver reports on system utilization (processor, memory, disk, and network) Use shell scripting to automate system maintenance tasks Network teaming: it is a new topic in RHCE el7 and also an important task of system admin for high availability of network service. So is an important topic for RHCE and I expect a question from teaming in RHCE exam. IPv6: RHCE course workbook does not content indept knowledge of IPv6, but due to lack of public IPv4 addresses, it is an important topic. So you should except an assignment and basic troubleshooting takes from IPv6 section. Firewalld: you should be able to configure firewalld for all all network services mention in Network services. In my professional life, I have to work a lot in port forwarding and natting. So I think there should be at least one question related to NAT or port forwarding from this section. sysctl: sysctl is an import command to work with customization of kernel parameter, it is also an important task of Linux system admin, so you can expect one question from this section as well. I this this topic as moderately important. Authenticate from kerbores: It is already covered in RHCSA, so I don t think it is important for RHCE.

7 Produce and deliver reports on system utilization: Even though this topic is important for monitoring server performance, which system admin has to do on daily basis. I believe it is moderately important for RHCE exam. But you can expect question combined with bash script. Bash script: Scripting is an important skill that a system admin should have. So I believe RHCE should include at least one question from this section. In RHCE workbook, only basic of Bash script is includes, so you should expect question basically from conditions and looping. However, question from expression and executing other program to display report may also be asked. Network services Network services are an important subset of the exam objectives. RHCE candidates should be capable of meeting the following objectives for each of the network services listed below: Install the packages needed to provide the service Configure SELinux to support the service Use SELinux port labeling to allow services to use non-standard ports Configure the service to start when the system is booted Configure the service for basic operation Configure host-based and user-based security for the service HTTP/HTTPS Configure a virtual host Configure private directories Deploy a basic CGI application Configure group-managed content Configure TLS security Virtual Hosting: It is an important skill from web server, professional. So you should expect a question from this section. Configure private directories: System admins don t use default folders they usually change root directory. So you should expect this question in exam. Not only that, but you will also have to work in SELinux to complete this task properly, which gives more importance to this task. So I think this is only of the very important questions from this section. Deploy a basic CGI Application: in RHCE EL7, CGI is less focused and it is replace by Web Server Gateway interface. So you should expect question from WSGI and PHP configuration for dynamic web application. Group-managed content: very important task as professionally multiple developers work in same folder. So this is an important task for RHCE exam.

8 Configure TLS security: I don t think this is an important because TLS security may be time consuming, if not done correctly. DNS Configure a caching-only name server Troubleshoot DNS client issues DNS: You are required to use same DNS that Kerberos provides, so I think this skill is less likely to come in Exam. Since, it is an easy task. Don t skip it. NFS Provide network shares to specific clients Provide network shares suitable for group collaboration Use Kerberos to control access to NFS network shares NFS share: Since, Kerberos is added in RHCE el7, you should expect a question from this section with Kerberos. However, group collaboration and shares to specific clients are also important task. SMB Provide network shares to specific clients Provide network shares suitable for group collaboration SMB: SMB is also covered in RHCSA so I think multiuser SMB is more important from this section. So there should be at least one question from this. SMTP Configure a system to forward all to a central mail server SMTP: Every server we administer as a system admin at least need to configure mail server to forward it to mail server, so this is important task. Since only mail forwarding is include, this topic is easy only.

9 SSH Configure key-based authentication Configure additional options described in documentation Key based authentication: already covered in RHCSA so it is less important. However you should be aware about other different options. Like, block root user to ssh, block X-forwarding, restrict users, allowing domains or IPs (hosts) using firewalld or TCP wrappers. NTP Synchronize time using other NTP peers NTP peers: I don t think is an important task for RHCE as configuration of time server is already covered in RHCSA and NTP peers configuration is not a challenging task. Database services Install and configure MariaDB Backup and restore a database Create a simple database schema Perform simple SQL queries against a database Installing and configuring MariaDB: Since this section is newly added topic, I expect at least one question from this section, So installing and configuration is the basis and so, I think, you will have to do it in RHCE. Backup and restore of database: professionally it is an important task, so you should expect a question on backup and restore of database. Physical backup/restore is not discussed in detail and LVM related questions are already covered in RHCSA. So, I don t think physical backup/restore is important. You should be able to logical backup and restore using dump command Creating a simple database schema: I think you may be asked to create database and assign user to the created database. Also, you will have to manage access permission to the database. Perform simple SQL queries against a database: RHCE workbook doesn t contain detail query statements so you should be ask question from select statements. Be prepare for different select statements including joints and grouping.