Output slurm config as facts (#176)

* output slurm config as facts

* address linter errors

* fix facts parsing 'SlurmctldParameters     = enable_configlessReturnToService=2'

* remove out of date test7

* skip broken mariadb on RL8

Author: sjpb

.github/workflows/ci.yml

@@ -53,15 +53,17 @@ jobs:
           - test4
           - test5
           - test6
-          - test7
           - test8
           - test9
           - test10
           - test11
           - test12
           - test13
           - test14
-        exclude: []
+        exclude:
+          # mariadb package provides /usr/bin/mysql on RL8 which doesn't work with geerlingguy/mysql role
+          - scenario: test4
+            image: 'rockylinux:8.9'
 
     steps:
       - name: Check out the codebase.

README.md

@@ -136,6 +136,14 @@ You will need to configure these variables if you have set `openhpc_enable.datab
 
 `openhpc_slurmdbd_mysql_username`: Username for authenticating with the database, defaults to `slurm`.
 
+## Facts
+
+This role creates local facts from the live Slurm configuration, which can be
+accessed (with facts gathering enabled) using `ansible_local.slurm`. As per the
+`scontrol show config` man page, uppercase keys are derived parameters and keys
+in mixed case are from from config files. Note the facts are only refreshed
+when this role is run.
+
 ## Example Inventory
 
 And an Ansible inventory as this:

filter_plugins/slurm_conf.py

@@ -91,11 +91,46 @@ def dict2parameters(d):
     parts = ['%s=%s' % (k, v) for k, v in d.items()]
     return ' '.join(parts)
 
+def config2dict(lines):
+    """ Convert a sequence of output lines from `scontrol show config` to a dict.
+        
+        As per man page uppercase keys are derived parameters, mixed case are from
+        from config files.
+
+        The following case-insensitive conversions of values are carried out:
+        - '(null)' and 'n/a' are converted to None.
+        - yes and no are converted to True and False respectively
+        
+        Except for these, values are always strings.
+    """
+    cfg = {}
+    for line in lines:
+        if '=' not in line: # ditch blank/info lines
+            continue
+        else:
+            parts = [x.strip() for x in line.split('=', maxsplit=1)] # maxplit handles '=' in values
+            if len(parts) != 2:
+                raise errors.AnsibleFilterError(f'line {line} cannot be split into key=value')
+            k, v = parts
+            small_v = v.lower()
+            if small_v == '(null)':
+                v = None
+            elif small_v == 'n/a':
+                v = None
+            elif small_v == 'no':
+                v = False
+            elif small_v == 'yes':
+                v = True
+            cfg[k] = v
+    return cfg
+
+
 class FilterModule(object):
 
     def filters(self):
         return {
             'hostlist_expression': hostlist_expression,
             'error': error,
             'dict2parameters': dict2parameters,
+            'config2dict': config2dict,
         }

handlers/main.yml

@@ -66,3 +66,7 @@
     - openhpc_slurm_service_started | bool
     - openhpc_enable.batch | default(false) | bool
     # 2nd condition required as notification happens on controller, which isn't necessarily a compute note
+
+- name: Reload facts
+  ansible.builtin.setup:
+    filter: ansible_local

molecule/README.md

@@ -14,7 +14,7 @@ test3  | 1            | Y                       | -
 test4  | 1            | N                       | 2x compute node, accounting enabled
 test5  | 1            | N                       | As for #1 but configless
 test6  | 1            | N                       | 0x compute nodes, configless
-test7  | 1            | N                       | 1x compute node, no login node so specified munge key, configless (checks image build should work)
+test7  | 1            | N                       | [removed, image build should just run install.yml task, this is not expected to work]
 test8  | 1            | N                       | 2x compute node, 2x login-only nodes, configless
 test9  | 1            | N                       | As test8 but uses `--limit=testohpc-control,testohpc-compute-0` and checks login nodes still end up in slurm.conf
 test10 | 1            | N                       | As for #5 but then tries to add an additional node

molecule/test7/converge.yml

@@ -0,0 +1,24 @@
+- name: Capture configuration from scontrol
+  # this includes any dynamically-generated config, not just what is set in
+  # slurm.conf
+  ansible.builtin.command: scontrol show config
+  changed_when: false
+  register: _scontrol_config
+
+- name: Create facts directory
+  ansible.builtin.file:
+    path: /etc/ansible/facts.d/
+    state: directory
+    owner: root
+    group: root
+    mode: ugo=rwX
+
+- name: Template slurm configuration facts
+  copy:
+    dest: /etc/ansible/facts.d/slurm.fact
+    content: "{{ _scontrol_config.stdout_lines | config2dict | to_nice_json }}"
+    owner: slurm
+    group: slurm
+    mode: ug=rw,o=r # any user can run scontrol show config anyway
+  register: _template_facts
+  notify: Reload facts

molecule/test7/molecule.yml

@@ -216,3 +216,5 @@
     enabled: "{{ openhpc_slurm_service_enabled | bool }}"
     state: "{{ 'started' if openhpc_slurm_service_started | bool else 'stopped' }}"
   when: openhpc_enable.batch | default(false) | bool
+
+- import_tasks: facts.yml