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Vault agent role for ansible #10

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Dec 1, 2024
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12 changes: 12 additions & 0 deletions roles/vault_agent/files/vault-agent-certificates.service
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[Unit]
Description=Vault Agent - retrieve Let's Encrypt certificates from Vault
After=network.target

[Service]
Type=notify
WorkingDirectory=/root/vault_agent_certificat
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Suggested change
WorkingDirectory=/root/vault_agent_certificat
WorkingDirectory=/root/vault_agent_certificates

Just to be consistent ^^
And when you have a path that is repeated in many places (here and in tasks.yml), you can create a default variable (in roles/vault_agent/defaults/main.yml) and reuse it everywhere, e.g.

vault_agent_working_directory: /root/vault_agent_certificates

ExecStart=/usr/bin/vault agent -config=agent-config.hcl
Restart=always

[Install]
WantedBy=multi-user.target
4 changes: 4 additions & 0 deletions roles/vault_agent/handlers/main.yml
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- name: Restart vault-agent-certificates
ansible.builtin.systemd:
name: vault-agent-certificates
state: restarted
97 changes: 97 additions & 0 deletions roles/vault_agent/tasks/main.yml
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- name: Download Vault Hashicorp gpg key
ansible.builtin.get_url:
url: https://apt.releases.hashicorp.com/gpg
dest: /usr/share/keyrings/hashicorp-archive-keyring.asc
mode: "0644"
owner: root
checksum: sha256:cafb01beac341bf2a9ba89793e6dd2468110291adfbb6c62ed11a0cde6c09029

- name: Add Vault repository
ansible.builtin.apt_repository:
repo: "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.asc] https://apt.releases.hashicorp.com {{ ansible_distribution_release }} main"
state: present

- name: Intall Vault
ansible.builtin.apt:
update_cache: true
name:
- vault
Comment on lines +22 to +26
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Maybe not for this PR as our needs are simple and Vault-Agent should be mostly compatible with any version of Vault server (https://developer.hashicorp.com/vault/docs/agent-and-proxy/agent/versions), but at some point we might want to pin a specific version of packages, especially Vault since it's a critical part of our infrastructure and we should check changelogs and ensure backups before upgrades.

The Ansible docs hint at vault=1.18.2 for example, however this doesn't prevent someone on the server from running apt update && apt upgrade and installing a different version, as this does not pin it for apt itself.
The surefire way to pin a version is to create a /etc/apt/preferences.d/vault.pref:

Explanation: Ansible - Vault pinning
Package: vault
Pin: version 1.18.2-*
Pin-Priority: 1000


- name: Retrieve role_id and secret_id from Vault
community.hashi_vault.vault_kv2_get:
path: certificat-web-id
register: certificat_secrets
run_once: true
delegate_to: localhost
become: false

- name: Create vault agent workdir
ansible.builtin.file:
path: /root/vault_agent_certificat
state: directory
mode: '0755'
owner: root
group: root

- name: Create role_id file
vars:
content: "{{ certificat_secrets.secret.role_id }}"
ansible.builtin.template:
src: content.j2
dest: /root/vault_agent_certificat/role_id
mode: '0600'
owner: root
group: root

- name: Create secret_id file
vars:
content: "{{ certificat_secrets.secret.secret_id }}"
ansible.builtin.template:
src: content.j2
dest: /root/vault_agent_certificat/secret_id
mode: '0600'
owner: root
group: root

- name: Copy agent-config.hcl
ansible.builtin.template:
src: agent-config.hcl.j2
dest: /root/vault_agent_certificat/agent-config.hcl
mode: '0644'
owner: root
group: root
notify: Restart vault-agent-certificates

- name: Copy retrieving_cert.tmpl
ansible.builtin.template:
src: retrieving_cert.tmpl.j2
dest: /root/vault_agent_certificat/retrieving_cert.tmpl
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It may be a good idea to change the template variable delimiters for this task so we don't have to escape all the {{ and }} in the retrieving_cert.tmpl file. This can be achieved by adding the following line : variable_start_string: << (see variable_start_string)

mode: '0644'
owner: root
group: root
variable_start_string: '<<'
variable_end_string: '>>'
notify: Restart vault-agent-certificates

- name: Copy vault-agent-certificates.service
ansible.builtin.copy:
src: vault-agent-certificates.service
dest: /etc/systemd/system/vault-agent-certificates.service
mode: '0644'
owner: root
group: root

- name: Create directory for certificates
ansible.builtin.file:
state: directory
dest: "{{ vault_agent_certificate_directory }}"
mode: '0755'
owner: root
group: root

- name: Start vault-agent-certificates service
ansible.builtin.systemd:
name: vault-agent-certificates
state: started
enabled: true
daemon_reload: true
40 changes: 40 additions & 0 deletions roles/vault_agent/templates/agent-config.hcl.j2
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vault {
address = "https://vault.rezoleo.fr"
retry {
num_retries = 5
}
}

auto_auth {
method {
type = "approle"

config = {
// create a role in vault with a policy able to "read" the secret
role_id_file_path = "role_id" // to change based on the path of the role_id file
secret_id_file_path = "secret_id" // to change based on the path of the secret_id file
remove_secret_id_file_after_reading = false
}
}

sinks {
sink {
type = "file"

config = {
path = "sink-token"
}
}
}
}

template {
source = "retrieving_cert.tmpl"
destination = "{{ vault_agent_certificate_directory }}/template_output"
perms = "0600"

exec {
command = {{service_reload_command | tojson}} {# to reload the service after retrieving the certificate #}
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Suggested change
command = {{service_reload_command | tojson}} {# to reload the service after retrieving the certificate #}
// command used to to reload the service after retrieving the certificate, in the form of ["binary", "arg1", "arg2"]
command = {{ vault_agent_service_reload_command | tojson }}

Also I found out that since we did this last year, the command is deprecated and replaced with exec 😅 https://developer.hashicorp.com/vault/docs/agent-and-proxy/agent/template#command

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If I am not mistaken the parameter command is not used directly but as a parameter of exec. Thus, I think this way of doing is not deprecated https://developer.hashicorp.com/vault/docs/agent-and-proxy/agent/template#exec

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Mondays are hard... You are right, sorry 😅


}
}
1 change: 1 addition & 0 deletions roles/vault_agent/templates/content.j2
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{{content}}
10 changes: 10 additions & 0 deletions roles/vault_agent/templates/retrieving_cert.tmpl.j2
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{{with secret "secret/certificat-web"}}
{{ index .Data.data "privkey.pem" | writeToFile "<<vault_agent_certificate_directory>>/privkey.pem" "" "" "0400" }}
{{ index .Data.data "chain.pem" | writeToFile "<<vault_agent_certificate_directory>>/chain.pem" "" "" "0400" }}
{{ index .Data.data "cert.pem" | writeToFile "<<vault_agent_certificate_directory>>/cert.pem" "" "" "0400" }}
{{ index .Data.data "fullchain.pem" | writeToFile "<<vault_agent_certificate_directory>>/fullchain.pem" "" "" "0400" }}
{{ index .Data.data "privkey.pem" }}
{{ index .Data.data "chain.pem" }}
{{ index .Data.data "cert.pem" }}
{{ index .Data.data "fullchain.pem" }}
{{end}}