RH294 - ch08s02

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Guided Exercise: Troubleshooting Playbooks

In this exercise, you will troubleshoot a playbook that has been given to you that does not work properly.

Outcomes

You should be able to troubleshoot and resolve issues in playbooks.

On workstation, run the lab troubleshoot-playbook start script. It verifies whether Ansible is installed on workstation. It also creates the /home/student/troubleshoot-playbook/ directory, and downloads to this directory the inventory, samba.yml, and samba.conf.j2 files from http://materials.example.com/labs/troubleshoot-playbook/.

[student@workstation ~]$ lab troubleshoot-playbook start

Procedure 8.1. Instructions

On workstation, change to the /home/student/troubleshoot-playbook/ directory.

[student@workstation ~]$ cd ~/troubleshoot-playbook/
[student@workstation troubleshoot-playbook]$

Create a file named ansible.cfg in the current directory. It should set the log_path parameter to write Ansible logs to the /home/student/troubleshoot-playbook/ansible.log file. It should set the inventory parameter to use the /home/student/troubleshoot-playbook/inventory file deployed by the lab script.
When you are finished, ansible.cfg should have the following contents:
```
[defaults]
log_path = /home/student/troubleshoot-playbook/ansible.log
inventory = /home/student/troubleshoot-playbook/inventory
```

Run the playbook. It will fail with an error.

This playbook would set up a Samba server if everything were correct. However, the run will fail due to missing double quotes on the random_var variable definition. Read the error message to see how ansible-playbook reports the problem. Notice the variable random_var is assigned a value that contains a colon and is not quoted.

[student@workstation troubleshoot-playbook]$ ansible-playbook samba.yml
ERROR! We were unable to read either as JSON nor YAML, these are the errors we got from each:
JSON: Expecting value: line 1 column 1 (char 0)

Syntax Error while loading YAML.
  mapping values are not allowed in this context

The error appears to be in '/home/student/troubleshoot-playbook/samba.yml': line 8, column 30, but may be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

    install_state: installed
    random_var: This is colon: test
                             ^ here

Confirm that the error has been properly logged to the /home/student/troubleshoot-playbook/ansible.log file.

[student@workstation troubleshoot-playbook]$ tail ansible.log

The error appears to be in '/home/student/troubleshoot-playbook/samba.yml': line 8, column 30, but may be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

    install_state: installed
    random_var: This is colon: test
                             ^ here

Edit the samba.yml playbook and correct the error by adding quotes to the entire value being assigned to random_var. The corrected version of the playbook contains the following content:
```
...output omitted...
  vars:
    install_state: installed
    random_var: "This is colon: test"
...output omitted...
```

Check the playbook using the --syntax-check option. Another error is issued due to extra white space in the indentation on the last task, deliver samba config.

[student@workstation troubleshoot-playbook]$ ansible-playbook --syntax-check \
> samba.yml
ERROR! We were unable to read either as JSON nor YAML, these are the errors we got from each:
JSON: Expecting value: line 1 column 1 (char 0)

Syntax Error while loading YAML.
  did not find expected key

The error appears to be in '/home/student/troubleshoot-playbook/samba.yml': line 44, column 4, but may be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:


   - name: deliver samba config
   ^ here

Edit the playbook and remove the extra space for all lines in that task. The corrected playbook should appear as follows:

...output omitted...
  - name: configure firewall for samba
    firewalld:
      state: enabled
      permanent: true
      immediate: true
      service: samba

  - name: deliver samba config
    template:
      src: templates/samba.conf.j2
      dest: /etc/samba/smb.conf
      owner: root
      group: root
      mode: 0644

Run the playbook using the --syntax-check option. An error is issued due to the install_state variable being used as a parameter in the install samba task. It is not quoted.

[student@workstation troubleshoot-playbook]$ ansible-playbook --syntax-check \
> samba.yml
ERROR! We were unable to read either as JSON nor YAML, these are the errors we got from each:
JSON: Expecting value: line 1 column 1 (char 0)

Syntax Error while loading YAML.
  found unacceptable key (unhashable type: 'AnsibleMapping')

The error appears to be in '/home/student/troubleshoot-playbook/samba.yml': line 14, column 15, but may be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

      name: samba
      state: {{ install_state }}
              ^ here
We could be wrong, but this one looks like it might be an issue with missing quotes. Always quote template expression brackets when they start a value. For instance:

    with_items:
      - {{ foo }}

Should be written as:

    with_items:
      - "{{ foo }}"

Edit the playbook and correct the install samba task. The reference to the install_state variable should be in quotes. The resulting file content should look like the following:
```
...output omitted...
  tasks:
  - name: install samba
    yum:
      name: samba
      state: "{{ install_state }}"
...output omitted...
```

Run the playbook using the --syntax-check option. It should not show any additional syntax errors.

[student@workstation troubleshoot-playbook]$ ansible-playbook --syntax-check \
> samba.yml

playbook: samba.yml

Run the playbook. An error, related to SSH, will be issued.

[student@workstation troubleshoot-playbook]$ ansible-playbook samba.yml
PLAY [Install a samba server] **************************************************

TASK [Gathering Facts] *********************************************************
fatal: [servera.lab.exammple.com]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: ssh: connect to host servera.lab.exammple.com port 22: Connection timed out", "unreachable": true}

PLAY RECAP *********************************************************************
servera.lab.exammple.com   : ok=0    changed=0    unreachable=1    failed=0  ...

Ensure the managed host servera.lab.example.com is running, using the ping command.

[student@workstation troubleshoot-playbook]$ ping -c3 servera.lab.example.com
PING servera.lab.example.com (172.25.250.10) 56(84) bytes of data.
64 bytes from servera.lab.example.com (172.25.250.10): icmp_seq=1 ttl=64 time=0.247 ms
64 bytes from servera.lab.example.com (172.25.250.10): icmp_seq=2 ttl=64 time=0.329 ms
64 bytes from servera.lab.example.com (172.25.250.10): icmp_seq=3 ttl=64 time=0.320 ms

--- servera.lab.example.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.247/0.298/0.329/0.041 ms

Ensure that you can connect to the managed host servera.lab.example.com as the devops user using SSH, and that the correct SSH keys are in place. Log off again when you have finished.

[student@workstation troubleshoot-playbook]$ ssh devops@servera.lab.example.com
Activate the web console with: systemctl enable --now cockpit.socket
...output omitted...
[devops@servera ~]$ exit
logout
Connection to servera.lab.example.com closed.

Rerun the playbook with -vvvv to get more information about the run. An error is issued because the servera.lab.example.com managed host is not reachable.

[student@workstation troubleshoot-playbook]$ ansible-playbook -vvvv samba.yml
...output omitted...

PLAYBOOK: samba.yml ******************************************************
1 plays in samba.yml

PLAY [Install a samba server] ********************************************

TASK [Gathering Facts] ***************************************************
task path: /home/student/troubleshoot-playbook/samba.yml:2
<servera.lab.exammple.com> ESTABLISH SSH CONNECTION FOR USER: devops
...output omitted...
fatal: [servera.lab.exammple.com]: UNREACHABLE! => {
    "changed": false,
    "msg": "Failed to connect to the host via ssh: OpenSSH_8.0p1, OpenSSL ... Control socket \"/home/student/.ansible/cp/d4775f48c9\" does not exist\r\ndebug2: resolving \"servera.lab.exammple.com\" port 22\r\ndebug2: ssh_connect_direct\r\ndebug1: Connecting to servera.lab.exammple.com [3.223.115.185] port 22.\r\ndebug2: fd 4 setting O_NONBLOCK\r\ndebug1: connect to address 3.223.115.185 port 22: Connection timed out\r\nssh: connect to host servera.lab.exammple.com port 22: Connection timed out",
    "unreachable": true
}

...output omitted...
PLAY RECAP ***************************************************************
servera.lab.exammple.com   : ok=0    changed=0    unreachable=1    failed=0

When using the highest level of verbosity with Ansible, examining the Ansible log file is a better option than checking console output. You might view the log file using the less command, or you might search for patterns in the log file using the grep command. Search for the word fatal in the /home/student/troubleshoot-playbook/ansible.log file.

[student@workstation troubleshoot-playbook]$ grep -i fatal ansible.log
2021-07-15 13:56:21,766 p=45752 u=student n=ansible | fatal: [servera.lab.exammple.com]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: ssh: connect to host servera.lab.exammple.com port 22: Connection timed out", "unreachable": true}
2021-07-15 14:22:43,262 p=46055 u=student n=ansible | fatal: [servera.lab.exammple.com]: UNREACHABLE! => {

Investigate the inventory file for errors. Notice the [samba_servers] group has misspelled servera.lab.example.com. Correct this error as shown below:
```
[samba_servers]
servera.lab.example.com
...output omitted...
```

Run the playbook again. The debug install_state variable task returns the message The state for the samba service is installed. This task makes use of the debug module, and displays the value of the install_state variable. An error is also shown in the deliver samba config task, because no samba.j2 file is available in the working directory, /home/student/troubleshoot-playbook/.

[student@workstation troubleshoot-playbook]$ ansible-playbook samba.yml

PLAY [Install a samba server] **************************************************
...output omitted...
TASK [debug install_state variable] ********************************************
ok: [servera.lab.example.com] => {
    "msg": "The state for the samba service is installed"
}
...output omitted...
TASK [deliver samba config] ****************************************************
fatal: [servera.lab.example.com]: FAILED! => {"changed": false, "msg": "Could not find or access 'samba.j2'\nSearched in:\n\t/home/student/troubleshoot-playbook/templates/samba.j2\n\t/home/student/troubleshoot-playbook/samba.j2\n\t/home/student/troubleshoot-playbook/templates/samba.j2\n\t/home/student/troubleshoot-playbook/samba.j2 on the Ansible Controller.\nIf you are using a module and expect the file to exist on the remote, see the remote_src option"}
...output omitted...
PLAY RECAP *********************************************************************
servera.lab.example.com    : ok=7    changed=3    unreachable=0    failed=1  ...

Edit the playbook, and correct the src parameter in the deliver samba config task to be samba.conf.j2. When you are finished it should look like the following:

...output omitted...
  - name: deliver samba config
    template:
      src: samba.conf.j2
      dest: /etc/samba/smb.conf
      owner: root
...output omitted...

Run the playbook again. Execute the playbook using the --step option. It should run without errors.

[student@workstation troubleshoot-playbook]$ ansible-playbook samba.yml --step

PLAY [Install a samba server] ************************************************
Perform task: TASK: Gathering Facts (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: install samba (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: install firewalld (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: debug install_state variable (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: start samba (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: start firewalld (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: configure firewall for samba (N)o/(y)es/(c)ontinue: y
...output omitted...
Perform task: TASK: deliver samba config (N)o/(y)es/(c)ontinue: y
...output omitted...
PLAY RECAP *********************************************************************
servera.lab.example.com    : ok=8    changed=1    unreachable=0    failed=0

Finish

On workstation, run the lab troubleshoot-playbook finish script to clean up this exercise.

[student@workstation ~]$ lab troubleshoot-playbook finish

This concludes the guided exercise.

Discuss Red Hat Enterprise Linux Automation with Ansible

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Red Hat Linux Automation with Ansible (RH294)

Haley_Ruccio

24 lip 2023

Learn how to automate Linux system administration tasks with Red Hat Ansible Automation PlatformRed Hat Enterprise Linux Automation with Ansible (RH294) is designed for Linux administrators and developers who need to automate repeatable and error-prone steps for system provisioning, configuration, application deployment, and orchestration. This course is based on Red Hat® Enterprise Linux® 9 and Red Hat Ansible Automation Platform 2.2.Course content summaryInstall Red Hat Ansible Automation Platform on control nodes.Create and update inventories of managed hosts and manage connections to them.Automate administration tasks with Ansible Playbooks and ad hoc commands.Write effective playbooks at scale.Protect sensitive data used by Ansible Automation Platform with Ansible Vault.Reuse code and simplify playbook development with Ansible Roles and Ansible Content Collections.Audience for this courseThis course is geared toward Linux system administrators, DevOps engineers, infrastructure automation engineers, and systems design engineers who are responsible for these tasks:Automating configuration managementEnsuring consistent and repeatable application deploymentProvisioning and deployment of development, testing, and production serversIntegrating with DevOps continuous integration/continuous delivery workflowsPrerequisites for this coursePass the Red Hat Certified System Administrator (RHCSA) exam (EX200), or demonstrate equivalent Red Hat Enterprise Linux knowledge and experience.Take our free assessment to gauge whether this offering is the best fit for your skills.

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curl finds no route to host?

TPeters

23 lip 2023

I am doing the self-paced course RH294 . With two exercises (Ch.3 final Lab and Ch.4 lab exercise 2) I ran into this problem:after installing and starting a web service, from the classroom web termicaI I cannot reach servera.lab.example.com with curl: "No route to host". This despite the fact that I can ping it, open a shell to it, and install the package on it with Ansible.Anyone else have the same problem?What might be the cause?

1702

Welcome to the Red Hat Linux Automation with Ansible (RH294) group in the Red Hat Learning Community

cschunke

18 lip 2023

We are excited to launch a space dedicated to the Red Hat Training course Red Hat Linux Automation with Ansible! To gain the most value from this group - click the "Join Group" button in the upper right hand corner.We encourage group members to collaborate in this group to discuss topics, ask questions, share best practices and tips, provide course feedback, and share their accomplishments as it relates to RH294.Read more about Red Hat Linux Automation with Ansible here.

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Revision: rh294-8.4-9cb53f0