This directory is where you should put any local or application specific event scripts for ctdb to call. All event scripts start with the prefic 'NN.' where N is a digit. The event scripts are run in sequence based on NN. Thus 10.interfaces will be run before 60.nfs. Each NN must be unique and duplicates will cause undefined behaviour. I.e. having both 10.interfaces and 10.otherstuff is not allowed. As a special case, any eventscript that ends with a '~' character will be ignored since this is a common postfix that some editors will append to older versions of a file. The eventscripts are called with varying number of arguments. The first argument is the "event" and the rest of the arguments depend on which event was triggered. All of the events except the 'shutdown' and 'startrecovery' events will be called with the ctdb daemon in NORMAL mode (ie. not in recovery) The events currently implemented are init This event does not take any additional arguments. This event is only invoked once, when ctdb is starting up. This event is used to do some cleanup work from earlier runs and prepare the basic setup. At this stage 'ctdb' commands won't work. Example: 00.ctdb cleans up $CTDB_BASE/state setup This event does not take any additional arguments. This event is only invoked once, when ctdb is starting up. This event is used to do some cleanup work from earlier runs and prepare the basic setup. Example: 00.ctdb cleans up $CTDB_BASE/state startup This event does not take any additional arguments. This event is only invoked once, when ctdb has finished the initial recoveries. This event is used to wait for the service to start and all resources for the service becoming available. This is used to prevent ctdb from starting up and advertize its services until all dependent services have become available. All services that are managed by ctdb should implement this event and use it to start the service. Example: 50.samba uses this event to start the samba daemon and then wait until samba and all its associated services have become available. It then also proceeds to wait until all shares have become available. shutdown This event is called when the ctdb service is shuting down. All services that are managed by ctdb should implement this event and use it to perform a controlled shutdown of the service. Example: 60.nfs uses this event to shut down nfs and all associated services and stop exporting any shares when this event is invoked. monitor This event is invoked every X number of seconds. The interval can be configured using the MonitorInterval tunable but defaults to 15 seconds. This event is triggered by ctdb to continously monitor that all managed services are healthy. When invoked, the event script will check that the service is healthy and return 0 if so. If the service is not healthy the event script should return non zero. If a service returns nonzero from this script this will cause ctdb to consider the node status as UNHEALTHY and will cause the public address and all associated services to be failed over to a different node in the cluster. All managed services should implement this event. Example: 10.interfaces which checks that the public interface (if used) is healthy, i.e. it has a physical link established. takeip This event is triggered everytime the node takes over a public ip address during recovery. This event takes three additional arguments : 'interface' 'ipaddress' and 'netmask' Before this event there will always be a 'startrecovery' event. This event will always be followed by a 'recovered' event once all ipaddresses have been reassigned to new nodes and the ctdb database has been recovered. If multiple ip addresses are reassigned during recovery it is possible to get several 'takeip' events followed by a single 'recovered' event. Since there might involve substantial work for the service when an ip address is taken over and since multiple ip addresses might be taken over in a single recovery it is often best to only mark which addresses are being taken over in this event and defer the actual work to reconfigure or restart the services until the 'recovered' event. Example: 60.nfs which just records which ip addresses are being taken over into a local state directory and which defers the actual restart of the services until the 'recovered' event. releaseip This event is triggered everytime the node releases a public ip address during recovery. This event takes three additional arguments : 'interface' 'ipaddress' and 'netmask' In all other regards this event is analog to the 'takeip' event above. Example: 60.nfs updateip This event is triggered everytime the node moves a public ip address between interfaces This event takes four additional arguments : 'old-interface' 'new-interface' 'ipaddress' and 'netmask' Example: 10.interface startrecovery This event is triggered everytime we start a recovery process or before we start changing ip address allocations. recovered This event is triggered every time we have finished a full recovery and also after we have finished reallocating the public ip addresses across the cluster. Example: 60.nfs which if the ip address configuration has changed during the recovery (i.e. if addresses have been taken over or released) will kill off any tcp connections that exist for that service and also send out statd notifications to all registered clients. stopped This event is called when a node is STOPPED and can be used to perform additional cleanup that is required. Note that a stopped node is considered inactive, so it will not be issuing the recovered event once the cluster has recovered. See 91.lvs for a use of this event. Additional note for takeip, releaseip, recovered: ALL services that depend on the ip address configuration of the node must implement all three of these events. ALL services that use TCP should also implement these events and at least kill off any tcp connections to the service if the ip address config has changed in a similar fashion to how 60.nfs does it. The reason one must do this is that ESTABLISHED tcp connections may survive when an ip address is released and removed from the host until the ip address is re-takenover. Any tcp connections that survive a release/takeip sequence can potentially cause the client/server tcp connection to get out of sync with sequence and ack numbers and cause a disruptive ack storm.
