Blaine Gardner
1391228b1d
mkdocs uses a markdown renderer that is hardcoded to 4 spaces per tab
for detecting indentation levels, including ordered- and
unordered-lists. Since we cannot easily change the renderer, begin using
a markdown linter in CI that will fail if official docs do not adhere to
the spacing rules.
As a starting point, the markdownlint config does not begin with the
default set of checks, which might overwhelm attempts to fix them.
Instead, focus on list-tab-spacing rules and a few other highly useful
checks.
markdownlint also has some gaps in its abilities that allow common Rook
doc issues to pass acceptance. However, it allows creating custom
linting plugins. Create 2 such linting plugins to check 2 things:
- all doc lines (except code blocks) must be aligned to a 4-space
boundary, without exception. This ensures that markdown will render
correctly with mkdocs. This unfortunately makes it possible to create
lists that are internally aligned strangely.
- admonitions must all follow the same format of
```
!!! header
body
```
For the strange lists, this is allowed and renders correctly, but it
looks strange:
```md
- first bullet
- second bullet
still second bullet
- third bullet
has a paragraph
of text inside
- last bullet
Signed-off-by: Blaine Gardner <blaine.gardner@ibm.com>
(cherry picked from commit c9d99e01a0)
2.1 KiB
title
| title |
|---|
| Stretch Storage Cluster |
For environments that only have two failure domains available where data can be replicated, consider the case where one failure domain is down and the data is still fully available in the remaining failure domain. To support this scenario, Ceph has integrated support for "stretch" clusters.
Rook requires three zones. Two zones (A and B) will each run all types of Rook pods, which we call the "data" zones. Two mons run in each of the two data zones, while two replicas of the data are in each zone for a total of four data replicas. The third zone (arbiter) runs a single mon. No other Rook or Ceph daemons need to be run in the arbiter zone.
For this example, we assume the desired failure domain is a zone. Another failure domain can also be specified with a known topology node label which is already being used for OSD failure domains.
apiVersion: ceph.rook.io/v1
kind: CephCluster
metadata:
name: rook-ceph
namespace: rook-ceph
spec:
dataDirHostPath: /var/lib/rook
mon:
# Five mons must be created for stretch mode
count: 5
allowMultiplePerNode: false
stretchCluster:
failureDomainLabel: topology.kubernetes.io/zone
subFailureDomain: host
zones:
- name: a
arbiter: true
- name: b
- name: c
cephVersion:
image: quay.io/ceph/ceph:v18.2.2
allowUnsupported: true
# Either storageClassDeviceSets or the storage section can be specified for creating OSDs.
# This example uses all devices for simplicity.
storage:
useAllNodes: true
useAllDevices: true
deviceFilter: ""
# OSD placement is expected to include the non-arbiter zones
placement:
osd:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: topology.kubernetes.io/zone
operator: In
values:
- b
- c
For more details, see the Stretch Cluster design doc.