From 0f4ac76c70cf0223d23ed7a4b0bf770ec00e8ccd Mon Sep 17 00:00:00 2001 From: Sebastian Wagner Date: Tue, 14 Sep 2021 16:43:17 +0200 Subject: [PATCH] doc/cephadm/service-management: Move Deployment of Daemons .. into "Daemon Placement" Signed-off-by: Sebastian Wagner (cherry picked from commit b68c99cd739d8f92784a3398e238e3ed6903046f) --- doc/cephadm/service-management.rst | 57 ++++++++++++++---------------- 1 file changed, 27 insertions(+), 30 deletions(-) diff --git a/doc/cephadm/service-management.rst b/doc/cephadm/service-management.rst index eaf0be9060f69..10d0280e4a512 100644 --- a/doc/cephadm/service-management.rst +++ b/doc/cephadm/service-management.rst @@ -172,8 +172,8 @@ specification. .. _orchestrator-cli-placement-spec: -Placement Specification -======================= +Daemon Placement +================ For the orchestrator to deploy a *service*, it needs to know where to deploy *daemons*, and how many to deploy. This is the role of a placement @@ -346,8 +346,8 @@ Or in YAML: host_pattern: "*" -Changing the number of monitors -------------------------------- +Changing the number of daemons +------------------------------ By specifying ``count``, only the number of daemons specified will be created: @@ -389,31 +389,11 @@ YAML can also be used to specify limits on hosts: - host2 - host3 -.. _orch-rm: - -Removing a Service -================== - -In order to remove a service including the removal -of all daemons of that service, run - -.. prompt:: bash - - ceph orch rm - -For example: - -.. prompt:: bash - - ceph orch rm rgw.myrgw - - -Deployment of Daemons -===================== +Algorithm description +--------------------- -Cephadm uses a declarative state to define the layout of the cluster. This -state consists of a list of service specifications containing placement -specifications (See :ref:`orchestrator-cli-service-spec` ). +Cephadm's declarative state consists of a list of service specifications +containing placement specifications. Cephadm continually compares a list of daemons actually running in the cluster against the list in the service specifications. Cephadm adds new daemons and @@ -456,12 +436,29 @@ Finally, cephadm removes daemons on hosts that are outside of the list of candidate hosts. .. note:: - + There is a special case that cephadm must consider. - If there are fewer hosts selected by the placement specification than + If there are fewer hosts selected by the placement specification than demanded by ``count``, cephadm will deploy only on the selected hosts. +.. _orch-rm: + +Removing a Service +================== + +In order to remove a service including the removal +of all daemons of that service, run + +.. prompt:: bash + + ceph orch rm + +For example: + +.. prompt:: bash + + ceph orch rm rgw.myrgw .. _cephadm-spec-unmanaged: -- 2.39.5