ha-manager.adoc

   1 [[chapter-ha-manager]]
   2 ifdef::manvolnum[]
   3 PVE({manvolnum})
   4 ================
   5 include::attributes.txt[]
   6
   7 NAME
   8 ----
   9
  10 ha-manager - Proxmox VE HA Manager
  11
  12 SYNOPSYS
  13 --------
  14
  15 include::ha-manager.1-synopsis.adoc[]
  16
  17 DESCRIPTION
  18 -----------
  19 endif::manvolnum[]
  20
  21 ifndef::manvolnum[]
  22 High Availability
  23 =================
  24 include::attributes.txt[]
  25 endif::manvolnum[]
  26
  27 'ha-manager' handles management of user-defined cluster services. This
  28 includes handling of user requests including service start, service
  29 disable, service relocate, and service restart. The cluster resource
  30 manager daemon also handles restarting and relocating services in the
  31 event of failures.
  32
  33 HOW IT WORKS
  34 ------------
  35
  36 The local resource manager ('pve-ha-lrm') is started as a daemon on
  37 each node at system start and waits until the HA cluster is quorate
  38 and locks are working.  After initialization, the LRM determines which
  39 services are enabled and starts them. Also the watchdog gets
  40 initialized.
  41
  42 The cluster resource manager ('pve-ha-crm') starts on each node and
  43 waits there for the manager lock, which can only be held by one node
  44 at a time.  The node which successfully acquires the manager lock gets
  45 promoted to the CRM, it handles cluster wide actions like migrations
  46 and failures.
  47
  48 When an node leaves the cluster quorum, its state changes to unknown.
  49 If the current CRM then can secure the failed nodes lock, the services
  50 will be 'stolen' and restarted on another node.
  51
  52 When a cluster member determines that it is no longer in the cluster
  53 quorum, the LRM waits for a new quorum to form. As long as there is no
  54 quorum the node cannot reset the watchdog. This will trigger a reboot
  55 after 60 seconds.
  56
  57 CONFIGURATION
  58 -------------
  59
  60 The HA stack is well integrated int the Proxmox VE API2. So, for
  61 example, HA can be configured via 'ha-manager' or the PVE web
  62 interface, which both provide an easy to use tool.
  63
  64 The resource configuration file can be located at
  65 '/etc/pve/ha/resources.cfg' and the group configuration file at
  66 '/etc/pve/ha/groups.cfg'. Use the provided tools to make changes,
  67 there shouldn't be any need to edit them manually.
  68
  69 RESOURCES/SERVICES AGENTS
  70 -------------------------
  71
  72 A resource or also called service can be managed by the
  73 ha-manager. Currently we support virtual machines and container.
  74
  75 GROUPS
  76 ------
  77
  78 A group is a collection of cluster nodes which a service may be bound to.
  79
  80 GROUP SETTINGS
  81 ~~~~~~~~~~~~~~
  82
  83 nodes::
  84
  85 list of group node members
  86
  87 restricted::
  88
  89 resources bound to this group may only run on nodes defined by the
  90 group. If no group node member is available the resource will be
  91 placed in the stopped state.
  92
  93 nofailback::
  94
  95 the resource won't automatically fail back when a more preferred node
  96 (re)joins the cluster.
  97
  98
  99 RECOVERY POLICY
 100 ---------------
 101
 102 There are two service recover policy settings which can be configured
 103 specific for each resource.
 104
 105 max_restart::
 106
 107 maximal number of tries to restart an failed service on the actual
 108 node.  The default is set to one.
 109
 110 max_relocate::
 111
 112 maximal number of tries to relocate the service to a different node.
 113 A relocate only happens after the max_restart value is exceeded on the
 114 actual node. The default is set to one.
 115
 116 Note that the relocate count state will only reset to zero when the
 117 service had at least one successful start. That means if a service is
 118 re-enabled without fixing the error only the restart policy gets
 119 repeated.
 120
 121 ERROR RECOVERY
 122 --------------
 123
 124 If after all tries the service state could not be recovered it gets
 125 placed in an error state. In this state the service won't get touched
 126 by the HA stack anymore.  To recover from this state you should follow
 127 these steps:
 128
 129 * bring the resource back into an safe and consistent state (e.g:
 130 killing its process)
 131
 132 * disable the ha resource to place it in an stopped state
 133
 134 * fix the error which led to this failures
 135
 136 * *after* you fixed all errors you may enable the service again
 137
 138
 139 SERVICE OPERATIONS
 140 ------------------
 141
 142 This are how the basic user-initiated service operations (via
 143 'ha-manager') work.
 144
 145 enable::
 146
 147 the service will be started by the LRM if not already running.
 148
 149 disable::
 150
 151 the service will be stopped by the LRM if running.
 152
 153 migrate/relocate::
 154
 155 the service will be relocated (live) to another node.
 156
 157 remove::
 158
 159 the service will be removed from the HA managed resource list. Its
 160 current state will not be touched.
 161
 162 start/stop::
 163
 164 start and stop commands can be issued to the resource specific tools
 165 (like 'qm' or 'pct'), they will forward the request to the
 166 'ha-manager' which then will execute the action and set the resulting
 167 service state (enabled, disabled).
 168
 169
 170 SERVICE STATES
 171 --------------
 172
 173 stopped::
 174
 175 Service is stopped (confirmed by LRM)
 176
 177 request_stop::
 178
 179 Service should be stopped. Waiting for confirmation from LRM.
 180
 181 started::
 182
 183 Service is active an LRM should start it ASAP if not already running.
 184
 185 fence::
 186
 187 Wait for node fencing (service node is not inside quorate cluster
 188 partition).
 189
 190 freeze::
 191
 192 Do not touch the service state. We use this state while we reboot a
 193 node, or when we restart the LRM daemon.
 194
 195 migrate::
 196
 197 Migrate service (live) to other node.
 198
 199 error::
 200
 201 Service disabled because of LRM errors. Needs manual intervention.
 202
 203
 204 ifdef::manvolnum[]
 205 include::pve-copyright.adoc[]
 206 endif::manvolnum[]
 207