Troubleshooting Common Scenarios

Apart from the problems that may arise in playbooks, another type of error relates to connectivity issues. To connect to managed hosts, SSH must be configured correctly, and also authentication and privilege escalation must work as expected.

Analyzing Connectivity Issues

To be able to connect to a managed host, you need to have an IP network connection. Apart from that, you need to make sure that the host has been set up correctly:

• The SSH service needs to be accessible on the remote host.

• Python must be installed.

• Privilege escalation needs to be set up.

Apart from these, inventory settings may be specified to indicate how to connect to a remote host. Normally, the inventory contains a host name only. If a host resolves to multiple IP addresses, you may want to specify how exactly the remote host must be connected to. The ansible_host parameter can be configured to do so. In inventory, for instance, you may include the following line to ensure that your host is connected in the right way:

ansible5.example.com ansible_host=192.168.4.55

Notice that this setting makes sense only in an environment where a host can be reached on multiple different IP addresses.

To test connectivity to remote hosts, you can use the ping module. It checks for IP connectivity, accessibility of the SSH service, sudo privilege escalation, and the availability of a Python stack. The ping module does not take any arguments. Listing 11-18 shows the result of running on the ad hoc command ansible all -m ping where hosts that are available send “pong” as a reply, and for hosts that are not available, you see why they are not available.

Listing 11-18 Verifying Connectivity Using the ping Module

::: pre_1 [ansible@control rhce8-book]$ ansible all -m ping ansible2 | SUCCESS => { “ansible_facts”: { “discovered_interpreter_python”: “/usr/libexec/platform-python” }, “changed”: false, “ping”: “pong” } ansible1 | SUCCESS => { “ansible_facts”: { “discovered_interpreter_python”: “/usr/libexec/platform-python” }, “changed”: false, “ping”: “pong” } ansible3 | SUCCESS => { “ansible_facts”: { “discovered_interpreter_python”: “/usr/libexec/platform-python” }, “changed”: false, “ping”: “pong” } ansible4 | FAILED! => { “msg”: “Missing sudo password” } :::

Analyzing Authentication Issues

A few settings play a role in authentication on the remote host to execute tasks:

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• The remote_user setting determines which user account to use on the managed nodes.

• SSH keys need to be configured for the remote_user to enable smooth authentication.

• The become parameter needs to be set to true.

• The become_user needs to be set to the root user account.

• Linux sudo needs to be set up correctly.

In Exercise 11-4 you work on troubleshooting some common scenarios.

::: box Exercise 11-4 Troubleshooting Connectivity Issues

1. Use an editor to create the file exercise114-1.yaml and give it the following contents:

---
- name: remove user from wheel group
  hosts: ansible4
  tasks:
  - user:
      name: ansible
      groups: ’’

2. Run the playbook using ansible-playbook exercise114-1.yaml and use ansible ansible4 -m reboot to reboot node ansible4.

3. Once the reboot is completed, use ansible all -m ping to verify connectivity. Host ansible4 should give a “Missing sudo password” error.

4. Type ansible ansible4 -m raw -a “usermod -aG wheel ansible” -u root -k to make user ansible a member of the group wheel again.

5. Repeat the ansible all -m ping command. You should now be able to connect normally to the host ansible4 again. :::