Add pool PGs count modification

Allows an administrator to adjust the PG count of a given pool. This can
be used to increase the PGs (for example after adding more OSDs) or
decrease it (to remove OSDs, reduce CPU load, etc.).

api-daemon/pvcapid/flaskapi.py

@@ -4459,6 +4459,50 @@ class API_Storage_Ceph_Pool_Element(Resource):
             reqargs.get("tier", None),
         )
 
+    @RequestParser(
+        [
+            {
+                "name": "pgs",
+                "required": True,
+                "helptext": "A placement group count must be specified.",
+            },
+        ]
+    )
+    @Authenticator
+    def put(self, pool, reqargs):
+        """
+        Adjust Ceph pool {pool}'s placement group count
+        ---
+        tags:
+          - storage / ceph
+        parameters:
+          - in: query
+            name: pgs
+            type: integer
+            required: true
+            description: The new number of placement groups (PGs) for the pool
+        responses:
+          200:
+            description: OK
+            schema:
+              type: object
+              id: Message
+          404:
+            description: Not found
+            schema:
+              type: object
+              id: Message
+          400:
+            description: Bad request
+            schema:
+              type: object
+              id: Message
+        """
+        return api_helper.ceph_pool_set_pgs(
+            pool,
+            reqargs.get("pgs", 0),
+        )
+
     @RequestParser(
         [
             {

api-daemon/pvcapid/helper.py

@@ -1434,6 +1434,22 @@ def ceph_pool_remove(zkhandler, name):
     return output, retcode
 
 
+@ZKConnection(config)
+def ceph_pool_set_pgs(zkhandler, name, pgs):
+    """
+    Set the PGs of a ceph RBD pool.
+    """
+    retflag, retdata = pvc_ceph.set_pgs_pool(zkhandler, name, pgs)
+
+    if retflag:
+        retcode = 200
+    else:
+        retcode = 400
+
+    output = {"message": retdata.replace('"', "'")}
+    return output, retcode
+
+
 @pvc_common.Profiler(config)
 @ZKConnection(config)
 def ceph_volume_list(zkhandler, pool=None, limit=None, is_fuzzy=True):

client-cli/pvc/cli_lib/ceph.py

@@ -708,7 +708,7 @@ def ceph_pool_info(config, pool):
 
 def ceph_pool_list(config, limit):
     """
-    Get list information about Ceph OSDs (limited by {limit})
+    Get list information about Ceph pools (limited by {limit})
 
     API endpoint: GET /api/v1/storage/ceph/pool
     API arguments: limit={limit}
@@ -728,7 +728,7 @@ def ceph_pool_list(config, limit):
 
 def ceph_pool_add(config, pool, pgs, replcfg, tier):
     """
-    Add new Ceph OSD
+    Add new Ceph pool
 
     API endpoint: POST /api/v1/storage/ceph/pool
     API arguments: pool={pool}, pgs={pgs}, replcfg={replcfg}, tier={tier}
@@ -747,7 +747,7 @@ def ceph_pool_add(config, pool, pgs, replcfg, tier):
 
 def ceph_pool_remove(config, pool):
     """
-    Remove Ceph OSD
+    Remove Ceph pool
 
     API endpoint: DELETE /api/v1/storage/ceph/pool/{pool}
     API arguments:
@@ -766,6 +766,27 @@ def ceph_pool_remove(config, pool):
     return retstatus, response.json().get("message", "")
 
 
+def ceph_pool_set_pgs(config, pool, pgs):
+    """
+    Set the PGs of a Ceph pool
+
+    API endpoint: PUT /api/v1/storage/ceph/pool/{pool}
+    API arguments: {"pgs": "{pgs}"}
+    API schema: {"message":"{data}"}
+    """
+    params = {"pgs": pgs}
+    response = call_api(
+        config, "put", "/storage/ceph/pool/{pool}".format(pool=pool), params=params
+    )
+
+    if response.status_code == 200:
+        retstatus = True
+    else:
+        retstatus = False
+
+    return retstatus, response.json().get("message", "")
+
+
 def format_list_pool(pool_list):
     # Handle empty list
     if not pool_list:

client-cli/pvc/pvc.py

@@ -3532,6 +3532,8 @@ def ceph_pool():
 def ceph_pool_add(name, pgs, tier, replcfg):
     """
     Add a new Ceph RBD pool with name NAME and PGS placement groups.
+
+    The placement group count must be a non-zero power of 2.
     """
 
     retcode, retmsg = pvc_ceph.ceph_pool_add(config, name, pgs, replcfg, tier)
@@ -3570,6 +3572,26 @@ def ceph_pool_remove(name, confirm_flag):
     cleanup(retcode, retmsg)
 
 
+###############################################################################
+# pvc storage pool set-pgs
+###############################################################################
+@click.command(name="set-pgs", short_help="Set PGs of an RBD pool.")
+@click.argument("name")
+@click.argument("pgs")
+@cluster_req
+def ceph_pool_set_pgs(name, pgs):
+    """
+    Set the placement groups (PGs) count for the pool NAME to PGS.
+
+    The placement group count must be a non-zero power of 2.
+
+    Placement group counts may be increased or decreased as required though frequent alteration is not recommended.
+    """
+
+    retcode, retmsg = pvc_ceph.ceph_pool_set_pgs(config, name, pgs)
+    cleanup(retcode, retmsg)
+
+
 ###############################################################################
 # pvc storage pool list
 ###############################################################################
@@ -5844,6 +5866,7 @@ ceph_osd.add_command(ceph_osd_list)
 
 ceph_pool.add_command(ceph_pool_add)
 ceph_pool.add_command(ceph_pool_remove)
+ceph_pool.add_command(ceph_pool_set_pgs)
 ceph_pool.add_command(ceph_pool_list)
 
 ceph_volume.add_command(ceph_volume_add)

daemon-common/ceph.py

@@ -513,6 +513,47 @@ def remove_pool(zkhandler, name):
     return True, 'Removed RBD pool "{}" and all volumes.'.format(name)
 
 
+def set_pgs_pool(zkhandler, name, pgs):
+    if not verifyPool(zkhandler, name):
+        return False, f'ERROR: No pool with name "{name}" is present in the cluster.'
+
+    # Validate new PGs count
+    pgs = int(pgs)
+    if (pgs == 0) or (pgs & (pgs - 1) != 0):
+        return (
+            False,
+            f'ERROR: Invalid PGs number "{pgs}": must be a non-zero power of 2.',
+        )
+
+    # Set the new pgs number
+    retcode, stdout, stderr = common.run_os_command(
+        f"ceph osd pool set {name} pg_num {pgs}"
+    )
+    if retcode:
+        return False, f"ERROR: Failed to set pg_num on pool {name} to {pgs}: {stderr}"
+
+    # Set the new pgps number if increasing
+    current_pgs = int(zkhandler.read(("pool.pgs", name)))
+    if current_pgs >= pgs:
+        retcode, stdout, stderr = common.run_os_command(
+            f"ceph osd pool set {name} pgp_num {pgs}"
+        )
+        if retcode:
+            return (
+                False,
+                f"ERROR: Failed to set pg_num on pool {name} to {pgs}: {stderr}",
+            )
+
+    # Update Zookeeper count
+    zkhandler.write(
+        [
+            (("pool.pgs", name), pgs),
+        ]
+    )
+
+    return True, f'Set PGs count to {pgs} for RBD pool "{name}".'
+
+
 def get_list_pool(zkhandler, limit, is_fuzzy=True):
     full_pool_list = zkhandler.children("base.pool")
 

docs/manuals/swagger.json

@@ -5414,6 +5414,42 @@
                 "tags": [
                     "storage / ceph"
                 ]
+            },
+            "put": {
+                "description": "",
+                "parameters": [
+                    {
+                        "description": "The new number of placement groups (PGs) for the pool",
+                        "in": "query",
+                        "name": "pgs",
+                        "required": true,
+                        "type": "integer"
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "OK",
+                        "schema": {
+                            "$ref": "#/definitions/Message"
+                        }
+                    },
+                    "400": {
+                        "description": "Bad request",
+                        "schema": {
+                            "$ref": "#/definitions/Message"
+                        }
+                    },
+                    "404": {
+                        "description": "Not found",
+                        "schema": {
+                            "$ref": "#/definitions/Message"
+                        }
+                    }
+                },
+                "summary": "Adjust Ceph pool {pool}'s placement group count",
+                "tags": [
+                    "storage / ceph"
+                ]
             }
         },
         "/api/v1/storage/ceph/snapshot": {