osd: set default bluestore_wal_devices empty

We only need to set the wal dedicated device when there's three tiers
of storage used.
Currently the block.wal partition will also be created on the same
device than block.db.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1685253

Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>

docs/source/osds/scenarios.rst

@@ -372,12 +372,11 @@ Example of what you will get:
    /dev/sda2: PARTLABEL="ceph block" PARTUUID="ea454807-983a-4cf2-899e-b2680643bc1c"
    /dev/sdb: PTTYPE="gpt"
    /dev/sdb1: PARTLABEL="ceph block.db" PARTUUID="af5b2d74-4c08-42cf-be57-7248c739e217"
-   /dev/sdb2: PARTLABEL="ceph block.wal" PARTUUID="af3f8327-9aa9-4c2b-a497-cf0fe96d126a"
 
 There is more device granularity for Bluestore ONLY if ``osd_objectstore: bluestore`` is enabled by setting the
 ``bluestore_wal_devices`` config option.
 
-By default, if ``bluestore_wal_devices`` is empty, it will get the content of ``dedicated_devices``.
+By default, if ``bluestore_wal_devices`` is empty.
 If set, then you will have a dedicated partition on a specific device for block.wal.
 
 Example of what you will get:

group_vars/osds.yml.sample

@@ -141,7 +141,6 @@ dummy:
 # /dev/sda2: PARTLABEL="ceph block" PARTUUID="ea454807-983a-4cf2-899e-b2680643bc1c"
 # /dev/sdb: PTTYPE="gpt"
 # /dev/sdb1: PARTLABEL="ceph block.db" PARTUUID="af5b2d74-4c08-42cf-be57-7248c739e217"
-# /dev/sdb2: PARTLABEL="ceph block.wal" PARTUUID="af3f8327-9aa9-4c2b-a497-cf0fe96d126a"
 #
 # Note: This scenario uses the ceph-disk tool to provision OSDs
 #dedicated_devices: []
@@ -151,7 +150,7 @@ dummy:
 #
 # ONLY if osd_objectstore: bluestore is enabled.
 #
-# By default, if 'bluestore_wal_devices' is empty, it will get the content of 'dedicated_devices'.
+# By default, if 'bluestore_wal_devices' is empty.
 # If set, then you will have a dedicated partition on a specific device for block.wal.
 #
 # Set bluestore_wal_devices: [] to use the same partition for RocksDB and WAL.
@@ -166,7 +165,7 @@ dummy:
 # /dev/sdc: PTTYPE="gpt"
 # /dev/sdc1: PARTLABEL="ceph block.wal" PARTUUID="824b84ba-6777-4272-bbbd-bfe2a25cecf3"
 # Note: This option uses the ceph-disk tool
-#bluestore_wal_devices: "{{ dedicated_devices }}"
+#bluestore_wal_devices: []
 
 # III. Use ceph-volume to create OSDs from logical volumes.
 # Use 'osd_scenario: lvm' to enable this scenario.

roles/ceph-osd/defaults/main.yml

@@ -133,7 +133,6 @@ valid_osd_scenarios:
 # /dev/sda2: PARTLABEL="ceph block" PARTUUID="ea454807-983a-4cf2-899e-b2680643bc1c"
 # /dev/sdb: PTTYPE="gpt"
 # /dev/sdb1: PARTLABEL="ceph block.db" PARTUUID="af5b2d74-4c08-42cf-be57-7248c739e217"
-# /dev/sdb2: PARTLABEL="ceph block.wal" PARTUUID="af3f8327-9aa9-4c2b-a497-cf0fe96d126a"
 #
 # Note: This scenario uses the ceph-disk tool to provision OSDs
 dedicated_devices: []
@@ -143,7 +142,7 @@ dedicated_devices: []
 #
 # ONLY if osd_objectstore: bluestore is enabled.
 #
-# By default, if 'bluestore_wal_devices' is empty, it will get the content of 'dedicated_devices'.
+# By default, if 'bluestore_wal_devices' is empty.
 # If set, then you will have a dedicated partition on a specific device for block.wal.
 #
 # Set bluestore_wal_devices: [] to use the same partition for RocksDB and WAL.
@@ -158,7 +157,7 @@ dedicated_devices: []
 # /dev/sdc: PTTYPE="gpt"
 # /dev/sdc1: PARTLABEL="ceph block.wal" PARTUUID="824b84ba-6777-4272-bbbd-bfe2a25cecf3"
 # Note: This option uses the ceph-disk tool
-bluestore_wal_devices: "{{ dedicated_devices }}"
+bluestore_wal_devices: []
 
 # III. Use ceph-volume to create OSDs from logical volumes.
 # Use 'osd_scenario: lvm' to enable this scenario.

roles/ceph-osd/tasks/scenarios/non-collocated.yml

@@ -29,6 +29,34 @@
     - osd_objectstore == 'filestore'
     - item.0.partitions|length == 0
 
+- name: prepare ceph "{{ osd_objectstore }}" containerized osd disk(s) non-collocated with a dedicated device for db
+  shell: |
+    docker run --net=host \
+    --pid=host \
+    --privileged=true \
+    --name=ceph-osd-prepare-{{ ansible_hostname }}-{{ item.1 | regex_replace('/dev/', '') }} \
+    -v /etc/ceph:/etc/ceph:z \
+    -v /var/lib/ceph/:/var/lib/ceph/:z \
+    -v /dev:/dev \
+    -v /etc/localtime:/etc/localtime:ro \
+    -e DEBUG=verbose \
+    -e CLUSTER={{ cluster }} \
+    -e CEPH_DAEMON=OSD_CEPH_DISK_PREPARE \
+    -e OSD_DEVICE={{ item.1 }} \
+    -e OSD_BLUESTORE_BLOCK_DB={{ item.2 }} \
+    {{ docker_env_args }} \
+    {{ ceph_osd_docker_prepare_env }} \
+    {{ ceph_docker_registry }}/{{ ceph_docker_image }}:{{ ceph_docker_image_tag }}
+  with_together:
+    - "{{ parted_results.results | default([]) }}"
+    - "{{ devices }}"
+    - "{{ dedicated_devices }}"
+  when:
+    - containerized_deployment
+    - osd_objectstore == 'bluestore'
+    - item.0.partitions|length == 0
+    - bluestore_wal_devices|length == 0
+
 - name: prepare ceph "{{ osd_objectstore }}" containerized osd disk(s) non-collocated with a dedicated device for db and wal
   shell: |
     docker run --net=host \
@@ -57,6 +85,7 @@
     - containerized_deployment
     - osd_objectstore == 'bluestore'
     - item.0.partitions|length == 0
+    - bluestore_wal_devices|length > 0
 
 - name: prepare ceph "{{ osd_objectstore }}" non-containerized osd disk(s) non-collocated
   command: "ceph-disk prepare {{ ceph_disk_cli_options }} {{ item.1 }} {{ item.2 }}"