r/v-m: Add role for Victoria Metrics

The *victoria-metrics* role deploys a single-server instance of the
Victoria Metrics time series database server.  It installs the selected
version by downloading the binary release from Github and copying it to
`/usr/local/sbin` on the managed node.  Scrape configuration is optional
and can be specified with the `scrape_configs` variable.

roles/victoria-metrics/tasks/deploy.yml

@@ -0,0 +1,73 @@
+- name: ensure victoria metrics user exists
+  user:
+    name: victoriametrics
+    system: true
+    home: /var/lib/victoria-metrics
+    createhome: false
+    shell: /sbin/nologin
+    state: present
+  tags:
+  - user
+
+- name: ensure victoria metrics data data directory exists
+  file:
+    path: /var/lib/victoria-metrics
+    owner: victoriametrics
+    group: victoriametrics
+    mode: u=rwx,go=rx
+    state: directory
+  tags:
+  - datadir
+
+- name: ensure /etc/sysconfig directory exists
+  file:
+    path: /etc/sysconfig
+    mode: u=rwx,go=rx
+    owner: root
+    group: root
+    state: directory
+  tags:
+  - config
+- name: ensure victoria metrics is configured
+  template:
+    src: victoria-metrics.sysconfig.j2
+    dest: /etc/sysconfig/victoria-metrics
+    mode: '0644'
+  notify:
+  - restart victoria-metrics
+  tags:
+  - config
+
+- name: ensure victoria metrics config directory exists
+  file:
+    path: /etc/victoria-metrics
+    mode: '0755'
+    state: directory
+  tags:
+  - config
+- name: ensure victoria metrics scrape configuration is set
+  copy:
+    dest: /etc/victoria-metrics/scrape.yml
+    content: '{{ vm_config|to_nice_yaml(indent=2) }}'
+    mode: '0644'
+  when: vm_config is not none
+  notify:
+  - reload victoria-metrics
+  tags:
+  - config
+  - scrape-config
+
+- name: ensure victoria metrics starts at boot
+  service:
+    name: victoria-metrics
+    enabled: true
+  tags:
+  - service
+  - systemd
+- name: ensure victoria metrics is running
+  service:
+    name: victoria-metrics
+    state: started
+  tags:
+  - service
+  - systemd