RH294 - ch06s02

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Guided Exercise: Selecting Hosts with Host Patterns

In this exercise, you explore how to use host patterns to specify hosts from the inventory for plays. You are provided with several example inventories to explore host patterns.

Outcomes

Use different host patterns to access various hosts in an inventory.

As the student user on the workstation machine, use the lab command to prepare your system for this exercise.

This command prepares your environment and ensures that all required resources are available.

[student@workstation ~]$ lab start projects-host

Procedure 6.1. Instructions

Change into the /home/student/projects-host directory, and review the playbook and inventory files in the directory.

[student@workstation ~]$ cd ~/projects-host
[student@workstation projects-host]$

List the contents of the directory.

[student@workstation projects-host]$ ls
ansible.cfg inventory1 inventory2 playbook.yml

Inspect the first example inventory file, inventory1. Observe how the inventory is organized. Identify what hosts and groups are in the inventory, and which domains are used.

srv1.example.com
srv2.example.com
s1.lab.example.com
s2.lab.example.com

[web]
jupiter.lab.example.com
saturn.example.com

[db]
db1.example.com
db2.example.com
db3.example.com

[lb]
lb1.lab.example.com
lb2.lab.example.com

[boston]
db1.example.com
jupiter.lab.example.com
lb2.lab.example.com

[london]
db2.example.com
db3.example.com
file1.lab.example.com
lb1.lab.example.com

[dev]
web1.lab.example.com
db3.example.com

[stage]
file2.example.com
db2.example.com

[prod]
lb2.lab.example.com
db1.example.com
jupiter.lab.example.com

[function:children]
web
db
lb
city

[city:children]
boston
london
environments

[environments:children]
dev
stage
prod
new

[new]
172.25.252.23
172.25.252.44
172.25.252.32

Inspect the second example inventory file, inventory2. Observe how this inventory is organized. Identify what hosts and groups are in the inventory, and which domains are used.

workstation.lab.example.com

[london]
servera.lab.example.com

[berlin]
serverb.lab.example.com

[tokyo]
serverc.lab.example.com

[atlanta]
serverd.lab.example.com

[europe:children]
london
berlin

Inspect the contents of the playbook, playbook.yml. It currently has db1.example.com as the host pattern for its play. Observe how that play uses the ansible.builtin.debug module to display the name of each managed host.
```
- name: Resolve host patterns
  hosts: db1.example.com
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"
```

Run the playbook.yml playbook using the inventory1 inventory file and review the output to verify that the db1.example.com server is present in the inventory1 inventory file.

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [db1.example.com] => {
    "msg": "db1.example.com"
}

PLAY RECAP *********************************************************************
db1.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the host pattern in the playbook to reference an IP address contained in the inventory1 inventory file. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: 172.25.252.44
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [172.25.252.44] => {
    "msg": "172.25.252.44"
}

PLAY RECAP *********************************************************************
172.25.252.44              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the host pattern to use the all group to list all managed hosts in the inventory1 inventory file. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: all
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [srv1.example.com] => {
    "msg": "srv1.example.com"
}
ok: [srv2.example.com] => {
    "msg": "srv2.example.com"
}
ok: [s1.lab.example.com] => {
    "msg": "s1.lab.example.com"
}
ok: [s2.lab.example.com] => {
    "msg": "s2.lab.example.com"
}
ok: [jupiter.lab.example.com] => {
    "msg": "jupiter.lab.example.com"
}
ok: [saturn.example.com] => {
    "msg": "saturn.example.com"
}
ok: [db1.example.com] => {
    "msg": "db1.example.com"
}
ok: [db2.example.com] => {
    "msg": "db2.example.com"
}
ok: [db3.example.com] => {
    "msg": "db3.example.com"
}
ok: [lb1.lab.example.com] => {
    "msg": "lb1.lab.example.com"
}
ok: [lb2.lab.example.com] => {
    "msg": "lb2.lab.example.com"
}
ok: [file1.lab.example.com] => {
    "msg": "file1.lab.example.com"
}
ok: [web1.lab.example.com] => {
    "msg": "web1.lab.example.com"
}
ok: [file2.example.com] => {
    "msg": "file2.example.com"
}
ok: [172.25.252.23] => {
    "msg": "172.25.252.23"
}
ok: [172.25.252.44] => {
    "msg": "172.25.252.44"
}
ok: [172.25.252.32] => {
    "msg": "172.25.252.32"
}

PLAY RECAP *********************************************************************
172.25.252.23              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
172.25.252.32              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
172.25.252.44              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db1.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db2.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db3.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file1.lab.example.com      : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file2.example.com          : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
jupiter.lab.example.com    : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb1.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb2.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s1.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s2.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
saturn.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv1.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv2.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
web1.lab.example.com       : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the host pattern to use the asterisk (*) character to list all hosts that end in .example.com in the inventory1 inventory file. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: '*example.com'
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [srv1.example.com] => {
    "msg": "srv1.example.com"
}
ok: [srv2.example.com] => {
    "msg": "srv2.example.com"
}
ok: [s1.lab.example.com] => {
    "msg": "s1.lab.example.com"
}
ok: [s2.lab.example.com] => {
    "msg": "s2.lab.example.com"
}
ok: [jupiter.lab.example.com] => {
    "msg": "jupiter.lab.example.com"
}
ok: [saturn.example.com] => {
    "msg": "saturn.example.com"
}
ok: [db1.example.com] => {
    "msg": "db1.example.com"
}
ok: [db2.example.com] => {
    "msg": "db2.example.com"
}
ok: [db3.example.com] => {
    "msg": "db3.example.com"
}
ok: [lb1.lab.example.com] => {
    "msg": "lb1.lab.example.com"
}
ok: [lb2.lab.example.com] => {
    "msg": "lb2.lab.example.com"
}
ok: [file1.lab.example.com] => {
    "msg": "file1.lab.example.com"
}
ok: [web1.lab.example.com] => {
    "msg": "web1.lab.example.com"
}
ok: [file2.example.com] => {
    "msg": "file2.example.com"
}

PLAY RECAP *********************************************************************
db1.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db2.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db3.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file1.lab.example.com      : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file2.example.com          : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
jupiter.lab.example.com    : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb1.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb2.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s1.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s2.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
saturn.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv1.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv2.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
web1.lab.example.com       : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

As you can see in the output of the preceding command, the *.example.com domain contains 14 hosts. Modify the host pattern so that hosts in the *.lab.example.com domain are ignored. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: '*.example.com, !*.lab.example.com'
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [srv1.example.com] => {
    "msg": "srv1.example.com"
}
ok: [srv2.example.com] => {
    "msg": "srv2.example.com"
}
ok: [saturn.example.com] => {
    "msg": "saturn.example.com"
}
ok: [db1.example.com] => {
    "msg": "db1.example.com"
}
ok: [db2.example.com] => {
    "msg": "db2.example.com"
}
ok: [db3.example.com] => {
    "msg": "db3.example.com"
}
ok: [file2.example.com] => {
    "msg": "file2.example.com"
}

PLAY RECAP *********************************************************************
db1.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db2.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db3.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file2.example.com          : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
saturn.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv1.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv2.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Without accessing the groups in the inventory1 inventory file, modify the host pattern to list these three hosts: lb1.lab.example.com, s1.lab.example.com, and db1.example.com. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: lb1.lab.example.com,s1.lab.example.com,db1.example.com
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [lb1.lab.example.com] => {
    "msg": "lb1.lab.example.com"
}
ok: [s1.lab.example.com] => {
    "msg": "s1.lab.example.com"
}
ok: [db1.example.com] => {
    "msg": "db1.example.com"
}

PLAY RECAP *********************************************************************
db1.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb1.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s1.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Use a wildcard host pattern to list hosts that start with a 172.25. IP address in the inventory1 inventory file. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: '172.25.*'
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [172.25.252.23] => {
    "msg": "172.25.252.23"
}
ok: [172.25.252.44] => {
    "msg": "172.25.252.44"
}
ok: [172.25.252.32] => {
    "msg": "172.25.252.32"
}

PLAY RECAP *********************************************************************
172.25.252.23              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
172.25.252.32              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
172.25.252.44              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Use a host pattern to list all hosts in the inventory1 inventory file that start with the letter "s". Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: 's*'
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [file2.example.com] => {
    "msg": "file2.example.com"
}
ok: [db2.example.com] => {
    "msg": "db2.example.com"
}
ok: [srv1.example.com] => {
    "msg": "srv1.example.com"
}
ok: [srv2.example.com] => {
    "msg": "srv2.example.com"
}
ok: [s1.lab.example.com] => {
    "msg": "s1.lab.example.com"
}
ok: [s2.lab.example.com] => {
    "msg": "s2.lab.example.com"
}
ok: [saturn.example.com] => {
    "msg": "saturn.example.com"
}

PLAY RECAP *********************************************************************
db2.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file2.example.com          : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s1.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s2.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
saturn.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv1.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
srv2.example.com           : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Notice the file2.example.com and db2.example.com hosts in the output of the preceding command. They appear in the list because they are both members of a group called stage, which also begins with the letter "s."

Using a list and wildcard host patterns, list all hosts in the inventory1 inventory in the prod group, those hosts with an IP address beginning with 172, and hosts that contain lab in their name. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: 'prod,172*,*lab*'
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [lb2.lab.example.com] => {
    "msg": "lb2.lab.example.com"
}
ok: [db1.example.com] => {
    "msg": "db1.example.com"
}
ok: [jupiter.lab.example.com] => {
    "msg": "jupiter.lab.example.com"
}
ok: [172.25.252.23] => {
    "msg": "172.25.252.23"
}
ok: [172.25.252.44] => {
    "msg": "172.25.252.44"
}
ok: [172.25.252.32] => {
    "msg": "172.25.252.32"
}
ok: [s1.lab.example.com] => {
    "msg": "s1.lab.example.com"
}
ok: [s2.lab.example.com] => {
    "msg": "s2.lab.example.com"
}
ok: [lb1.lab.example.com] => {
    "msg": "lb1.lab.example.com"
}
ok: [file1.lab.example.com] => {
    "msg": "file1.lab.example.com"
}
ok: [web1.lab.example.com] => {
    "msg": "web1.lab.example.com"
}

PLAY RECAP *********************************************************************
172.25.252.23              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
172.25.252.32              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
172.25.252.44              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db1.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
file1.lab.example.com      : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
jupiter.lab.example.com    : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb1.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
lb2.lab.example.com        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s1.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
s2.lab.example.com         : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
web1.lab.example.com       : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

List all hosts that belong to both the db and london groups. Run the playbook using the inventory1 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: db,&london
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory1

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [db2.example.com] => {
    "msg": "db2.example.com"
}
ok: [db3.example.com] => {
    "msg": "db3.example.com"
}

PLAY RECAP *********************************************************************
db2.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
db3.example.com            : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the hosts value in the playbook.yml file so that all servers in the london group are targeted. Run the playbook using the inventory2 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: london
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory2

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [servera.lab.example.com] => {
    "msg": "servera.lab.example.com"
}

PLAY RECAP *********************************************************************
servera.lab.example.com    : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the hosts value in the playbook.yml file so that all servers in the europe nested group are targeted. Run the playbook using the inventory2 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: europe
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory2

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [servera.lab.example.com] => {
    "msg": "servera.lab.example.com"
}
ok: [serverb.lab.example.com] => {
    "msg": "serverb.lab.example.com"
}

PLAY RECAP *********************************************************************
servera.lab.example.com    : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
serverb.lab.example.com    : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the hosts value in the playbook.yml file so that all servers that do not belong to any group are targeted. Run the playbook using the inventory2 inventory file.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: ungrouped
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory2

PLAY [Resolve host patterns] ***************************************************

TASK [Display managed hosts matching the host pattern] *************************
ok: [workstation.lab.example.com] => {
    "msg": "workstation.lab.example.com"
}

PLAY RECAP *********************************************************************
workstation.lab.example.com : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Modify the hosts value in the playbook.yml file to specify a group that does not exist in the inventory2 inventory file. Run the playbook using the inventory2 inventory file. Note the message in the output that no match for that host pattern was found.

[student@workstation projects-host]$ cat playbook.yml
---
- name: Resolve host patterns
  hosts: australia
  gather_facts: no
  tasks:
  - name: Display managed hosts matching the host pattern
    ansible.builtin.debug:
      msg: "{{ inventory_hostname }}"

[student@workstation projects-host]$ ansible-navigator run \
> -m stdout playbook.yml -i inventory2

[WARNING]: Could not match supplied host pattern, ignoring: australia

PLAY [Resolve host patterns] ***************************************************
skipping: no hosts matched

PLAY RECAP *********************************************************************

Finish

On the workstation machine, change to the student user home directory and use the lab command to complete this exercise.

This step is important to ensure that resources from previous exercises do not impact upcoming exercises.

[student@workstation ~]$ lab finish projects-host

This concludes the section.

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.

980

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.

351

Revision: rh294-9.0-c95c7de