software:
* Use reliable ``server'' components
-
++
NOTE: Computer components with same functionality can have varying
reliability numbers, depending on the component quality. Most vendors
sell components with higher reliability as ``server'' components -
times of about 2 minutes, so you can get no more than 99.999%
availability.
+
Requirements
------------
+You must meet the following requirements before you start with HA:
+
* at least three cluster nodes (to get reliable quorum)
* shared storage for VMs and containers
* hardware redundancy (everywhere)
+* use reliable “server” components
+
* hardware watchdog - if not available we fall back to the
linux kernel software watchdog (`softdog`)
automatically distributed to the cluster nodes, and all nodes share
the same HA configuration.
+
+Resources
+~~~~~~~~~
+
The resource configuration file `/etc/pve/ha/resources.cfg` stores
the list of resources managed by `ha-manager`. A resource configuration
inside that list look like this:
----
-<sid>:
+<type>:<name>
<property> <value>
...
----
+It starts with a resource type followed by a resource specific name,
+separated with colon. Together this forms the HA resource ID, which is
+used by all `ha-manager` commands to uniquely identify a resource
+(example: `vm:100` or `ct:101`).
+
It starts with the service ID followed by a collon. The next lines
contain additional properties:
include::ha-resources-opts.adoc[]
+Groups
+~~~~~~
+
The HA group configuration file `/etc/pve/ha/groups.cfg` is used to
define groups of cluster nodes. A resource can be restricted to run
-only on the members of such group.
+only on the members of such group. A group configuration look like
+this:
+----
+group: <group>
+ nodes <node_list>
+ <property> <value>
+ ...
+----
+include::ha-groups-opts.adoc[]
Node Power Status