Managing Server Processes

This chapter covers starting and stopping OpenDJ directory server. In this chapter you will learn to:

Start, restart, and stop OpenDJ directory server using OpenDJ command-line tools, OpenDJ control panel, or system service integration on Linux and Windows systems
Understand how to recognize that OpenDJ directory server is recovering from a crash or abrupt shutdown
Configure whether OpenDJ directory server loads data into cache at server startup before accepting client connections

Starting a Server

Use one of the following techniques:

Use the start-ds command, described in start-ds(1) in the Reference:
```
$ start-ds
```
Alternatively, you can specify the --no-detach option to start the server in the foreground.
(Linux) If OpenDJ directory server was installed from a .deb or .rpm package, then service management scripts were created at setup time.

Use the service opendj start command:
```
centos# service opendj start
Starting opendj (via systemctl):                           [  OK  ]
```
```
ubuntu$ sudo service opendj start
$Starting opendj: > SUCCESS.
```

(UNIX) Create an RC script by using the create-rc-script command, described in create-rc-script(1) in the Reference, and then use the script to start the server.

Unless you run OpenDJ on Linux as root, use the --userName userName option to specify the user who installed OpenDJ:

$ sudo create-rc-script \
 --outputFile /etc/init.d/opendj \
 --userName mark

$ sudo /etc/init.d/opendj start

For example, if you run OpenDJ on Linux as root, you can use the RC script to start the server at system boot, and stop the server at system shutdown:

$ sudo update-rc.d opendj defaults
update-rc.d: warning: /etc/init.d/opendj missing LSB information
update-rc.d: see <http://wiki.debian.org/LSBInitScripts>
 Adding system startup for /etc/init.d/opendj ...
   /etc/rc0.d/K20opendj -> ../init.d/opendj
   /etc/rc1.d/K20opendj -> ../init.d/opendj
   /etc/rc6.d/K20opendj -> ../init.d/opendj
   /etc/rc2.d/S20opendj -> ../init.d/opendj
   /etc/rc3.d/S20opendj -> ../init.d/opendj
   /etc/rc4.d/S20opendj -> ../init.d/opendj
   /etc/rc5.d/S20opendj -> ../init.d/opendj

(Windows) Register OpenDJ as a Windows Service by using the windows-service command, described in windows-service(1) in the Reference, and then manage the service through Windows administration tools:
```
C:\path\to\opendj\bat> windows-service.bat --enableService
```

By default OpenDJ saves a compressed version of the server configuration used on successful startup. This ensures that the server provides a last known good configuration, which can be used as a reference or copied into the active configuration if the server fails to start with the current active configuration. It is possible, though not usually recommended, to turn this behavior off by changing the global server setting save-config-on-successful-startup to false.

Stopping a Server

Although OpenDJ directory server is designed to recover from failure and disorderly shutdown, it is safer to shut the server down cleanly, because a clean shutdown reduces startup delays during which OpenDJ server attempts to recover database backend state, and prevents situations where OpenDJ server cannot recover automatically.

Follow these steps to shut down OpenDJ server cleanly:

(Optional) If you are stopping a replicated server permanently, for example, before decommissioning the underlying system or virtual machine, first remove the server from the replication topology:
```
$ dsreplication \
 disable \
 --disableAll \
 --port 4444 \
 --hostname opendj.example.com \
 --adminUID admin \
 --adminPassword password \
 --trustAll \
 --no-prompt
```
This step unregisters the server from the replication topology, effectively removing its replication configuration from other servers. This step must be performed before you decommission the system, because the server must connect to its peers in the replication topology.
Before shutting down the system where OpenDJ server is running, and before detaching any storage used for directory data, cleanly stop the server using one of the following techniques:
- Use the stop-ds command, described in stop-ds(1) in the Reference:
  $ stop-ds
- (Linux) If OpenDJ directory server was installed from a .deb or .rpm package, then service management scripts were created at setup time.
  
  Use the service opendj stop command:
  centos# service opendj stop Stopping opendj (via systemctl): [ OK ]
  ubuntu$ sudo service opendj stop $Stopping opendj: ... > SUCCESS.
- (UNIX) Create an RC script, and then use the script to stop the server:
  $ sudo create-rc-script \ --outputFile /etc/init.d/opendj \ --userName mark $ sudo /etc/init.d/opendj stop
- (Windows) Register OpenDJ as a Windows Service, and then manage the service through Windows administration tools:
  C:\path\to\opendj\bat> windows-service.bat --enableService
Do not intentionally kill the OpenDJ server process unless the server is completely unresponsive.

When stopping cleanly, the server writes state information to database backends, and releases locks that it holds on database files.

Restarting a Server

Use one of the following techniques:

Use the stop-ds command:
```
$ stop-ds --restart
```

(Linux) If OpenDJ directory server was installed from a .deb or .rpm package, then service management scripts were created at setup time.

Use the service opendj restart command:

centos# service opendj restart
Restarting opendj (via systemctl):                         [  OK  ]

ubuntu$ sudo service opendj restart
$Stopping opendj: ... > SUCCESS.

$Starting opendj: > SUCCESS.

(UNIX) Create an RC script, and then use the script to stop the server:

$ sudo create-rc-script \
 --outputFile /etc/init.d/opendj \
 --userName mark

$ /etc/init.d/opendj restart

(Windows) Register OpenDJ as a Windows Service, and then manage the service through Windows administration tools:
```
C:\path\to\opendj\bat> windows-service.bat --enableService
```

Server Recovery

OpenDJ tends to show resilience when restarting after a crash or after the server process is killed abruptly. OpenDJ might have to replay the last few entries in a transaction log. Generally, OpenDJ returns to service quickly.

Database recovery messages are found in the database log file, such as /path/to/opendj/db/userRoot/dj.log.

The following example shows two example messages from the recovery log. The first message is written at the beginning of the recovery process. The second message is written at the end of the process:

111104 10:23:48:967 CONFIG [/path/to/opendj/db/userRoot]Recovery
 underway, found end of log
...
111104 10:23:49:015 CONFIG [/path/to/opendj/db/userRoot]Recovery finished:
 Recovery Info ...

What can take some time during server startup is preloading database content into memory when the server starts. Objects cached in memory do not survive a crash. By default, OpenDJ does not cache objects in memory before starting to accept client requests. You can, however, set the preload-time-limit property for the database cache of your backend if you do want to load objects into the database cache before OpenDJ begins accepting client connections.