Exercise 1.4: Adding members to a pool on F5

Objective

Demonstrate use of the BIG-IP pool member module to tie web server nodes into the load balancing pool http_pool created in the previous exercises.

Guide

Step 1:

Use VS Code Explorer to create a new file called bigip-pool-members.yml.

The Ansible node is equiped with Visual Studio Code and can be accessed via UDF ACCESS Methods.

Step 2:

Enter the following play definition into bigip-pool-members.yml:

---
- name: BIG-IP SETUP
  hosts: lb
  connection: local
  gather_facts: false
  • The --- at the top of the file indicates that this is a YAML file.
  • The hosts: lb, indicates the play is run only on the lb group. Technically there only one F5 device but if there were multiple they would be configured simultaneously.
  • connection: local tells the Playbook to run locally (rather than SSHing to itself)
  • gather_facts: false disables facts gathering. We are not using any fact variables for this playbook.

Do not exit the editor yet.

Step 3

Next, append the first task to above playbook. This task will use the bigip_pool_member module configure the two RHEL web servers as nodes on the BIG-IP F5 load balancer.

tasks:

- name: ADD POOL MEMBERS
  bigip_pool_member:
    provider:
      server: "{{private_ip}}"
      user: "{{ansible_user}}"
      password: "{{ansible_ssh_pass}}"
      server_port: 8443
      validate_certs: no
    state: "present"
    name: "{{hostvars[item].inventory_hostname}}"
    host: "{{hostvars[item].ansible_host}}"
    port: "80"
    pool: "http_pool"
  loop: "{{ groups['webservers'] }}"

Explanation of each line within the task: - name: ADD POOL MEMBERS is a user defined description that will display in the terminal output. - bigip_pool_member: tells the task which module to use.

Next we have module parameters - The server: "{{private_ip}}" parameter tells the module to connect to the F5 BIG-IP IP address, which is stored as a variable private_ip in inventory - The provider: parameter is a group of connection details for the BIG-IP. - The user: "{{ansible_user}}" parameter tells the module the username to login to the F5 BIG-IP device with - The password: "{{ansible_ssh_pass}}" parameter tells the module the password to login to the F5 BIG-IP device with - The server_port: 8443 parameter tells the module the port to connect to the F5 BIG-IP device with - The state: "present" parameter tells the module we want this to be added rather than deleted. - The name: "{{hostvars[item].inventory_hostname}}" parameter tells the module to use the inventory_hostname as the name (which will be host1 and host2). - The host: "{{hostvars[item].ansible_host}}" parameter tells the module to add a web server IP address already defined in our inventory. - The port: parameter tells the pool member port. - The pool: "http_pool" parameter tells the module to put this node into a pool named http_pool - The validate_certs: "no" parameter tells the module to not validate SSL certificates. This is just used for demonstration purposes since this is a lab. Finally there is a loop parameter which is at the task level (it is not a module parameter but a task level parameter: - loop: tells the task to loop over the provided list. The list in this case is the group webservers which includes two RHEL hosts.

Save the file and exit out of editor.

Step 4

Run the playbook - exit back into the command line of the control host and execute the following:

[student1@ansible ~]$ ansible-playbook bigip-pool-members.yml

Playbook Output

The output will look as follows.

[student1@ansible ~]$ ansible-playbook bigip-pool-members.yml

PLAY [BIG-IP SETUP] ************************************************************

TASK [ADD POOL MEMBERS] ********************************************************
changed: [f5] => (item=host1)
changed: [f5] => (item=host2)

PLAY RECAP *********************************************************************
f5                         : ok=1    changed=1    unreachable=0    failed=0

Output parsing

Let’s use the bigip_device_info to collect the pool members on BIG-IP. JSON query is a powerful filter that can be used. Please go through before proceeding.

Use VS Code Explorer to create a new file called display-pool-members.yml.

Enter the following:

---
- name: "List pool members"
  hosts: lb
  gather_facts: false
  connection: local

  tasks:

  - name: Query BIG-IP facts
    bigip_device_info:
      provider:
        server: "{{private_ip}}"
        user: "{{ansible_user}}"
        password: "{{ansible_ssh_pass}}"
        server_port: 8443
        validate_certs: "no"
      gather_subset:
       - ltm-pools
    register: bigip_device_facts

  - name: "View complete output"
    debug: "msg={{bigip_device_facts}}"

  - name: "Show members belonging to pool"
    debug: "msg={{item}}"
    loop: "{{bigip_device_facts.ltm_pools | json_query(query_string)}}"
    vars:
     query_string: "[?name=='http_pool'].members[*].name[]"
  • vars: in the module is defining a variable query_string to be used within the module itself
  • query_String will have the name of all members from pool name ‘http_pool’. query_string is defined to make it easier to read the entire json string

Execute the playbook

[student1@ansible ~]$ ansible-playbook display-pool-members.yml

Output

[student1@ansible 1.4-add-pool-members]$ ansible-playbook display-pool-members.yml

PLAY [List pool members] ******************************************************************************************************************************************************************************

TASK [Query BIG-IP facts] *****************************************************************************************************************************************************************************
changed: [f5]

TASK [View complete output] ***************************************************************************************************************************************************************************
ok: [f5] =>
  msg:
    changed: true
    ltm_pools:
    - allow_nat: 'yes'
      allow_snat: 'yes'
      client_ip_tos: pass-through
      client_link_qos: pass-through
      full_path: /Common/http_pool
      ignore_persisted_weight: 'no'
      lb_method: round-robin
      members:
      - address: 54.191.xx.xx
        connection_limit: 0
        dynamic_ratio: 1
        ephemeral: 'no'
        fqdn_autopopulate: 'no'
        full_path: /Common/host1:80
        inherit_profile: 'yes'
        logging: 'no'
        monitors: []
        name: host1:80
        partition: Common
        priority_group: 0
        rate_limit: 'no'
        ratio: 1
        state: disabled
      - address: 54.200.xx.xx
        connection_limit: 0
        dynamic_ratio: 1
        ephemeral: 'no'
        fqdn_autopopulate: 'no'
        full_path: /Common/host2:80
        inherit_profile: 'yes'
        logging: 'no'
        monitors: []
        name: host2:80
        partition: Common
        priority_group: 0
        rate_limit: 'no'
        ratio: 1
        state: disabled
      minimum_active_members: 0
      minimum_up_members: 0
      minimum_up_members_action: failover
      minimum_up_members_checking: 'no'
      monitors:
      - /Common/http
      name: http_pool
      priority_group_activation: 0
      queue_depth_limit: 0
      queue_on_connection_limit: 'no'
      queue_time_limit: 0
      reselect_tries: 0
      server_ip_tos: pass-through
      server_link_qos: pass-through
      service_down_action: none
      slow_ramp_time: 10

TASK [Show members belonging to pool] *****************************************************************************************************************************************************************
ok: [f5] => (item=host1:80) =>
  msg: host1:80
ok: [f5] => (item=host2:80) =>
  msg: host2:80

PLAY RECAP ********************************************************************************************************************************************************************************************
f5                         : ok=3    changed=1    unreachable=0    failed=0

Solution

The finished Ansible Playbook is provided here for an Answer key. Click here: bigip-pool-members.yml.

Verifying the Solution

Login to the F5 with your web browser to see what was configured.

In the Compnent tab On the BIG-IP click the ACCESS drop down then the TMUI link.

Login information for the BIG-IP: - username: admin - password: provided by instructor defaults to f5ansible

The pool will now show two members (host1 and host2). Click on Local Traffic-> then click on Pools. Click on http_pool to get more granular information. Click on the Members tab in the middle to list all the Members. f5members

You have finished this exercise.