[[Configuration_file_history]]
= Configuration file history

The management operations may modify the model. When this occurs the xml
backing the model is written out again reflecting the latest changes. In
addition a full history of the file is maintained. The history of the
file goes in a separate directory under the configuration directory.

As mentioned in <<Command_line_parameters,Command line parameters>> the default
configuration file can be selected using a command-line parameter. For a
standalone server instance the history of the active `standalone.xml` is
kept in `jboss.server.config.dir`/standalone_xml_history (See
<<Command_line_parameters,Command line parameters#standalone_system_properties>>
for more details). For a domain the active `domain.xml` and `host.xml`
histories are kept in `jboss.domain.config.dir`/domain_xml_history and
`jboss.domain.config.dir`/host_xml_history.

The rest of this section will only discuss the history for
`standalone.xml`. The concepts are exactly the same for `domain.xml` and
`host.xml`.

Within `standalone_xml_history` itself following a successful first time
boot we end up with three new files:

* `standalone.initial.xml` - This contains the original configuration
that was used the first time we successfully booted. This file will
never be overwritten. You may of course delete the history directory and
any files in it at any stage.
* `standalone.boot.xml` - This contains the original configuration that
was used for the last successful boot of the server. This gets
overwritten every time we boot the server successfully.
* `standalone.last.xml` - At this stage the contents will be identical
to `standalone.boot.xml`. This file gets overwritten each time the
server successfully writes the configuration, if there was an unexpected
failure writing the configuration this file is the last known successful
write.

`standalone_xml_history` contains a directory called `current` which
should be empty. Now if we execute a management operation that modifies
the model, for example adding a new system property using the CLI:

[source,options="nowrap"]
----
[standalone@localhost:9990 /] /system-property=test:add(value="test123")
{"outcome" => "success"}
----

What happens is:

* The original configuration file is backed up to
`standalone_xml_history/current/standalone.v1.xml`. The next change to
the model would result in a file called `standalone.v2.xml` etc. The 100
most recent of these files are kept.
* The change is applied to the original configuration file
* The changed original configuration file is copied to
`standalone.last.xml`

When restarting the server, any existing
`standalone_xml_history/current` directory is moved to a new timestamped
folder within the `standalone_xml_history`, and a new `current` folder
is created. These timestamped folders are kept for 30 days.

[[snapshots-file-history]]
== Snapshots

In addition to the backups taken by the server as described above you
can manually take take snapshots which will be stored in the `snapshot`
folder under the `_xml_history` folder, the automatic backups described
above are subject to automatic house keeping so will eventually be
automatically removed, the snapshots on the other hand can be entirely
managed by the administrator.

You may also take your own snapshots using the CLI:

[source,options="nowrap"]
----
[standalone@localhost:9990 /] :take-snapshot
{
    "outcome" => "success",
    "result" => {"name" => "/Users/kabir/wildfly/standalone/configuration/standalone_xml_history/snapshot/20110630-172258657standalone.xml"}
}
----

You can also use the CLI to list all the snapshots

[source,options="nowrap"]
----
[standalone@localhost:9990 /] :list-snapshots
{
    "outcome" => "success",
    "result" => {
        "directory" => "/Users/kabir/wildfly/standalone/configuration/standalone_xml_history/snapshot",
        "names" => [
            "20110630-165714239standalone.xml",
            "20110630-165821795standalone.xml",
            "20110630-170113581standalone.xml",
            "20110630-171411463standalone.xml",
            "20110630-171908397standalone.xml",
            "20110630-172258657standalone.xml"
        ]
    }
}
----

To delete a particular snapshot:

[source,options="nowrap"]
----
[standalone@localhost:9990 /] :delete-snapshot(name="20110630-165714239standalone.xml")
{"outcome" => "success"}
----

and to delete all snapshots:

[source,options="nowrap"]
----
[standalone@localhost:9990 /] :delete-snapshot(name="all")
{"outcome" => "success"}
----

In domain mode executing the snapshot operations against the root node
will work against the domain model. To do this for a host model you need
to navigate to the host in question:

[source,options="nowrap"]
----
[domain@localhost:9990 /] /host=master:list-snapshots
{
    "outcome" => "success",
    "result" => {
        "domain-results" => {"step-1" => {
            "directory" => "/Users/kabir/wildfly/domain/configuration/host_xml_history/snapshot",
            "names" => [
                "20110630-141129571host.xml",
                "20110630-172522225host.xml"
            ]
        }},
        "server-operations" => undefined
    }
}
----

[[subsequent-starts]]
== Subsequent Starts

For subsequent server starts it may be desirable to take the state of
the server back to one of the previously known states, for a number of
items an abbreviated reverence to the file can be used:

[cols=",,",options="header"]
|=======================================================================
|Abreviation |Parameter |Description

|initial |--server-config=initial |This will start the server using the
initial configuration first used to start the server.

|boot |--server-config=boot |This will use the configuration from the
last successful boot of the server.

|last |--server-config=last |This will start the server using the
configuration backed up from the last successful save.

|v? |--server-config=v? |This will server the _xml_history/current
folder for the configuration where ? is the number of the backup to use.

|-? |--server-config=-? |The server will be started after searching the
snapshot folder for the configuration which matches this prefix.
|=======================================================================

In addition to this the `--server-config` parameter can always be used
to specify a configuration relative to the `jboss.server.config.dir` and
finally if no matching configuration is found an attempt to locate the
configuration as an absolute path will be made.
