Skip to content

Latest commit

 

History

History
370 lines (267 loc) · 14.4 KB

README-Exercies.md

File metadata and controls

370 lines (267 loc) · 14.4 KB
Raw

Notes_crt_rh294

Requirements

There are 18 questions in total. You will need five RHEL 8 (or CentOS 😎 virtual machines to be able to successfully complete all questions.

Optional Automatic Exam Setup Available

Here is an automated exam environment deployment for Mac/Linux/Windows that deploys the practice exam environment for you, including IPA server/client installation and configuration. You can also use your own lab environment. Navigate to the respective repo you wish to use for this practice exam and follow the README instructions:

https://github.com/rdbreak/rhce8env, https://github.com/rdbreak/ansible27env, https://github.com/rdbreak/ansible8env.

Check the included README.md for the environment info and instructions. Reach out to @rdbreak with any questions or concerns.

One VM will be configured as an Ansible control node. Other four VMs will be used to apply playbooks to solve the sample exam questions. The following FQDNs will be used throughout the sample exam.

control.example.com – Ansible control node

node1.example.com – managed node

node2.example.com – managed node

node3.example.com – managed node

node4.example.com – managed node

There are a couple of requirements that should be met before proceeding further:

control.example.com server has password-less SSH access to all managed servers (using the root user). node1:4.example.com servers have a 5GB secondary /dev/sdb disk attached. There is a regular “user” created on all the servers.

Tips and Suggestions

  • I tried to cover as many exam objectives as possible, however, note that there will be no questions related to dynamic inventory.
  • Some questions may depend on the outcome of others. Please read all questions before proceeding.

Sample Exam Questions

Note - you have root access to all servers.

Task 1: Ansible Installation and Configuration

(If you’re using the automated deployments, Ansible is already installed) Install the ansible package on the control node (including any dependencies) and configure the following:

Create a regular user automation with the password of devops. Use this user for all sample exam tasks. All playbooks and other Ansible configuration that you create for this sample exam should be stored in /home/automation/plays. Create a configuration file /home/automation/plays/ansible.cfg to meet the following requirements:

  1. The roles path should include /home/automation/plays/roles, as well as any other path that may be required for the course of the sample exam.
  2. The inventory file path is /home/automation/plays/inventory.
  3. Privileged escalation is disabled by default.
  4. Ansible should be able to manage 10 hosts at a single time.
  5. Ansible should connect to all managed nodes using the automation user.

Create an inventory file /home/automation/plays/inventory with the following:

  1. node1.ansi.example.com should be a member of the proxy host group.
  2. node2.ansi.example.com should be a member of the webservers host group.
  3. node3.ansi.example.com should be a member of the webservers and database host group.
  4. node4.ansi.example.com should be a member of the database host group.

Task 2: Ad-Hoc Commands

Create an SSH keypair. Write a script /home/automation/plays/adhoc that uses Ansible ad-hoc commands to achieve the following:

  1. User automation is created on all inventory hosts.
  2. SSH key (that you generated) is copied to all inventory hosts for the automation user and stored in /home/automation/.ssh/authorized_keys.
  3. The automation user is allowed to elevate privileges on all inventory hosts without having to provide a password.
  4. After running the ad-hoc script, you should be able to SSH into all inventory hosts using the automation user without password, as well as a run all privileged commands.

Task 3: File Content

Create a playbook /home/automation/plays/motd.yml that runs on all inventory hosts and does the following:

  1. The playbook should replace any existing content of /etc/motd with text. Text depends on the host group.
  2. On hosts in the proxy host group the line should be “Welcome to HAProxy server”.
  3. On hosts in the webservers host group the line should be “Welcome to Apache server”.
  4. On hosts in the database host group the line should be “Welcome to MySQL server”.

Task 4: Configure SSH Server

Create a playbook /home/automation/plays/sshd.yml that runs on all inventory hosts and configures SSHD daemon as follows:

  1. banner is set to /etc/motd
  2. X11Forwarding is disabled
  3. MaxAuthTries is set to 3

Task 5: Ansible Vault

Create Ansible vault file /home/automation/plays/secret.yml. Encryption/decryption password is devops. Add the following variables to the vault:

  1. user_password with value of devops
  2. database_password with value of devops
  3. Store Ansible vault password in the file /home/automation/plays/vault_key.

Task 6: Users and Groups

You have been provided with the list of users below. Use /home/automation/plays/vars/user_list.yml file to save this content.

---
users:
- username: alice
  uid: 1201
- username: vincent
  uid: 1202
- username: sandy
  uid: 2201
- username: patrick
  uid: 2202

Create a playbook /home/automation/plays/users.yml that uses the vault file /home/automation/plays/secret.yml to achieve the following:

  1. Users whose user ID starts with 1 should be created on servers in the webservers host group. User password should be used from the user_password variable.
  2. Users whose user ID starts with 2 should be created on servers in the database host group. User password should be used from the user_password variable.
  3. All users should be members of a supplementary group wheel.
  4. Shell should be set to /bin/bash for all users.
  5. Account passwords should use the SHA512 hash format.
  6. Each user should have an SSH key uploaded (use the SSH key that you create previously).

After running the playbook, users should be able to SSH into their respective servers without passwords.

Task 7: Scheduled Tasks

Create a playbook /home/automation/plays/regular_tasks.yml that runs on servers in the proxy host group and does the following:

  1. A root crontab record is created that runs every hour.
  2. The cron job appends the file /var/log/time.log with the output from the date command.

Task 8: Software Repositories

Create a playbook /home/automation/plays/repository.yml that runs on all servers and does the following:

  1. A YUM repository file is created.
  2. The name of the repository is rpms.
  3. The description of the repository is “This is the main repo file”.
  4. Repositories are available to use from http://repo.ansi.example.com/BaseOS and http://repo.ansi.example.com/AppStream

Task 9: Create and Work with Roles

Create a role called sample-mysql and store it in /home/automation/plays/roles. The role should satisfy the following requirements:

  1. A primary partition number 1 of size 800MB on device /dev/sdb is created.
  2. An LVM volume group called vg_database is created that uses the primary partition created above.
  3. An LVM logical volume called lv_mysql is created of size 512MB in the volume group vg_database.
  4. An XFS filesystem on the logical volume lv_mysql is created.
  5. Logical volume lv_mysql is permanently mounted on /mnt/mysql_backups.
  6. mariadb package is installed.
  7. Firewall is configured to allow all incoming traffic on MySQL port TCP 3306.
  8. MySQL root user password should be set from the variable database_password (see task #5).
  9. MySQL server should be started and enabled on boot.
  10. MySQL server configuration file is generated from the my.cnf.j2 Jinja2 template with the following content:
[mysqld]
bind_address = {{ ansible_default_ipv4.address }}
skip_name_resolve datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

Create a playbook /home/automation/plays/mysql.yml that uses the role and runs on hosts in the database host group.

Task 10: Create and Work with Roles (Some More)

Create a role called sample-apache and store it in /home/automation/plays/roles. The role should satisfy the following requirements:

  1. The httpd, mod_ssl and php packages are installed. Apache service is running and enabled on boot.
  2. Firewall is configured to allow all incoming traffic on HTTP port TCP 80 and HTTPS port TCP 443.
  3. Apache service should be restarted every time the file /var/www/html/index.html is modified.
  4. A Jinja2 template file index.html.j2 is used to create the file /var/www/html/index.html with the following content:
The address of the server is: {{ ansible_default_ipv4.address }}

{{ ansible_default_ipv4.address }} is the IP address of the managed node. Create a playbook /home/automation/plays/apache.yml that uses the role and runs on hosts in the webservers host group.

Task 11: Download Roles From an Ansible Galaxy and Use Them

Use Ansible Galaxy to download and install geerlingguy.haproxy role in /home/automation/plays/roles. Create a playbook /home/automation/plays/haproxy.yml that runs on servers in the proxy host group and does the following:

  1. Use geerlingguy.haproxy role to load balance request between hosts in the webservers host group.
  2. Use roundrobin load balancing method.
  3. HAProxy backend servers should be configured for HTTP only (port 80).
  4. Firewall is configured to allow all incoming traffic on port TCP 80.

If your playbook works, then doing “**curl http://node1.ansi.example.com/**” should return output from the web server (see task #10). Running the command again should return output from the other web server.

Task 12: Security

Create a playbook /home/automation/plays/selinux.yml that runs on hosts in the webservers host group and does the following:

  1. Uses the selinux RHEL system role.
  2. Enables httpd_can_network_connect SELinux boolean.
  3. The change must survive system reboot.

Task 13: Use Conditionals to Control Play Execution

Create a playbook /home/automation/plays/sysctl.yml that runs on all inventory hosts and does the following:

  1. If a server has more than 512MB of RAM, then parameter vm.swappiness is set to 10.
  2. If a server has less than 512MB of RAM, then the following error message is displayed: Server memory less than 512MB

Task 14: Use Archiving

Create a playbook /home/automation/plays/archive.yml that runs on hosts in the database host group and does the following:

  1. A file /mnt/mysql_backups/database_list.txt is created that contains the following line: dev,test,qa,prod.
  2. A gzip archive of the file /mnt/mysql_backups/database_list.txt is created and stored in /mnt/mysql_backups/archive.gz.

Task 15: Work with Ansible Facts

Create a playbook /home/automation/plays/facts.yml that runs on hosts in the database host group and does the following:

  1. A custom Ansible fact server_role=mysql is created that can be retrieved from ansible_local.custom.sample_exam when using Ansible setup module.

Task 16: Software Packages

Create a playbook /home/automation/plays/packages.yml that runs on all inventory hosts and does the following:

  1. Installs tcpdump and mailx packages on hosts in the proxy host groups.
  2. Installs lsof and mailx and packages on hosts in the database host groups.

Task 17: Services

Create a playbook /home/automation/plays/target.yml that runs on hosts in the webservers host group and does the following:

  1. Sets the default boot target to multi-user.

Task 18. Create and Use Templates to Create Customized Configuration Files

Create a playbook /home/automation/plays/server_list.yml that does the following:

  1. Playbook uses a Jinja2 template server_list.j2 to create a file /etc/server_list.txt on hosts in the database host group.
  2. The file /etc/server_list.txt is owned by the automation user.
  3. File permissions are set to 0600.
  4. SELinux file label should be set to net_conf_t.
  5. The content of the file is a list of FQDNs of all inventory hosts.

After running the playbook, the content of the file /etc/server_list.txt should be the following:

node1.ansi.example.com node2.ansi.example.com node3.ansi.example.com

Note - If the FQDN of any inventory host changes, re-running the playbook should update the file with the new values.

Validate Ansible

Control Nodes

yum list installed platform-python

subscription-manager register
subscription-manager repos --enable ansible-2-for-rhel-8-x86_64-rpms
yum install ansible

# Validate
ansible --version
ansible -m setup localhost | grep ansible_python_version

Managed Hosts

yum module install python36

Config Files order

1 ./ansible.cfg 2 ~/.ansible.cfg 3 /etc/ansible/ansible.cfg

[defaults]
inventory = ./inventory
remote_user = user
ask_pass = false

[privilege_escalation]
become = true
become_method = sudo
become_user = root
become_ask_pass = false
```sh

Static inventory

```sh
sudo vim /etc/ansible/hosts
[nodes]
node-[1:10].server.com

[db]
db-[99:101].server.com

[webserver]
node-[a:b].server.com

[tecnology:children]
webserver
db

Validate inventory

ansible all -i inventory --list-hosts
ansible ungrouped -i inventory --list-hosts
ansible [group] -i inventory --list-hosts

Coppy SSH

ssh-copy-id root@[node-hostname]

/etc/sudoers.d
.. user ALL=(ALL) NOPASSWD:ALL

Execute playbooks

# module
ansible host-pattern -m module [-a 'module arguments'] [-i inventory] -o

# playbook
ansible-playbook -i inventory {or} [servers-scoupe] playbook.yml

#Test
ansible-playbook -i inventory {or} [servers-scoupe] -C playbook.yml

Validate module

ansible-doc -s [module]

Validate playbook syntax

ansible-playbook --syntax-check playbook.yml

Proyect structure

project
├── ansible.cfg
├── group_vars
│   ├── datacenters
│   ├── datacenters1
│   └── datacenters2
├── host_vars
│   ├── host1
│   ├── host2
│   ├── host3
├── inventory
└── playbook.yml
│   ├── host3
├── roles
│   ├── role1