add lnet configuration

Author: sjpb

ansible/filesystems.yml

@@ -32,4 +32,5 @@
   tasks:
     - include_role:
         name: lustre
+        # NB install is ONLY run in builder
         tasks_from: configure.yml

ansible/roles/lustre/README.md

@@ -5,16 +5,18 @@ Install and configure a Lustre client. This builds RPM packages from source.
 **NB:** The `install.yml` playbook in this role should only be run during image build, with the default `update_enable=true`. This ensures that the latest kernel and matching
 `kernel-devel` packages will be installed. This playbook is not idempotent.
 
+**NB:** Currently this only supports RockyLinux 9.
+
 ## Role Variables
 
-- `lustre_version`: Optional str. Version of lustre to build, default '2.15.64'. TODO: EXPLAIN. See https://wiki.whamcloud.com/display/PUB/Lustre+Support+Matrix
+- `lustre_version`: Optional str. Version of lustre to build, default '2.15.5' which is the first version with EL9 support
 - `lustre_mounts`: Required list. Define Lustre filesystems and mountpoints as a list of dicts with possible keys:
     - `mgs_nid`: The NID for the MGS, e.g. `192.168.227.11@tcp1`
     - `fs_name`: The name of the filesystem to mount
     - `mount_point`: Path to mount filesystem at. Default is `/mnt/lustre/{{ lustre_fs_name}}`
     - `mount_state`: Mountpoint state, as for [ansible.posix.mount](https://docs.ansible.com/ansible/latest/collections/ansible/posix/mount_module.html#parameter-state). Default `mounted`.
   Any of these parameters may alternatively be specified as role variables prefixed `lustre_`. If both are given entries in `lustre_mounts` take priority.
-
+- `lustre_subnet_cidr`: Required str. CIDR of subnet for interface to be used for Lustre.
 The following variables control the package build and and install and should not generally be required:
 - `lustre_build_packages`: Optional list. Prerequisite packages required to build Lustre. See `defaults/main.yml`.
 - `lustre_build_dir`: Optional str. Path to build lustre at, default `/tmp/lustre-release`.

ansible/roles/lustre/defaults/main.yml

@@ -1,5 +1,6 @@
 lustre_version: '2.15.5' # https://www.lustre.org/lustre-2-15-5-released/
 lustre_mounts: []
+#lustre_subnet_cidr:
 #lustre_mgs_nid:
 #lustre_fs_name:
 lustre_mount_point: "/mnt/lustre/{{ lustre_fs_name }}"

ansible/roles/lustre/tasks/configure.yml

@@ -1,3 +1,34 @@
+- name: Gather interface info
+  shell:
+    cmd: |
+      ip -o -f inet addr show | awk '{print $2, $4}' | awk -F/ '{print $1}'
+  changed_when: false
+  register: _inet_interfaces
+
+- name: Set fact for Lustre interface
+  set_fact:
+    _lustre_interface: "{{ item.0 }}"
+  when: lustre_subnet_cidr | ansible.utils.network_in_usable(item.1)
+  loop: "{{ _inet_interfaces.stdout_lines | map('split') }}"
+
+- name: Ensure Lustre interface found
+  assert:
+    that: _lustre_interface is defined
+    fail_msg: "No interface was found for lustre_subnet_cidr={{ lustre_subnet_cidr }}"
+
+- name: Write LNet configuration file
+  template:
+    src: lnet.conf.j2
+    dest:  /etc/lnet.conf # exists from package install
+    owner: root
+    group: root
+    mode: u=rw,go=r # from package install
+  register: _lnet_conf
+
+- name: Import LNet configuration
+  command: lnetctl import /etc/lnet.conf
+  when: _lnet_conf.changed
+
 - name: Ensure mount points exist
   ansible.builtin.file:
     path: "{{ item.mount_point | default(lustre_mount_point) }}/{{ item.fs_name | default(lustre_fs_name) }}"