How to re-baseline a Component-based Snapshot
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Whenever you make changes to a Component Template that has been used to take a Snapshot, you'll need to re-execute or re-baseline your Snapshots.
BMC Server Automation Snapshot Jobs are designed to collect information associated with the group of servers that they are targeted to run on. These jobs are typically used to collect server inventory information, and can also be used to track configuration changes to servers.
A snapshot job has certain attributes associated with it, such as its description, its schedule, which defines when and how often it will run, and the list of servers that the job is targeted to run against. In addition, a snapshot job also has an associated Component Template, which defines the specific configuration items that will be collected on each server that the job is targeted to run on. These configuration items are stored in tables in the BMC Server Automation database.
The first time that a particular snapshot job is run, the job collects all configuration items defined by its associated Component Template. This initial set of data collected by the first run of a snapshot job is known as a "baseline". If no changes are made to either the job or its associated template between runs of the same snapshot job, subsequent runs of the job will only collect configuration items whose values have changed since the last time the job was run.
Snapshot jobs and their associated Component Templates are maintained as versioned objects within the BSA system. If any changes are made to either of these objects in between runs of a snapshot job, their versions will get incremented and the next run of the snapshot job will store new values in the database for every configuration item collected by the job on every server that the job runs against, regardless of whether or not their values have changed since the last job run. This is known as "rebaselining" the snapshot.
Changes to the Snapshot Job or Component Template
It is important to note that any change to any attribute of the snapshot job or its associated component template will trigger a rebaselining to occur. Examples of the attributes of a snapshot job whose modification would trigger a rebaselining include the job's description, schedule, or list of servers that the job is targeted to run against. Note that this is not an exhaustive list, and it is worth re-emphasizing that any change to any attribute of the job will trigger a rebaselining.
Similarly, examples of changes that could be made to a component template associated with a snapshot job that would trigger a rebaselining include adding a template part, removing a template part, or modifying an existing template part. Again this is not an exhaustive list, and it should be noted that any change to the component template associated with a snapshot job will trigger a rebaselining
The most important concepts to be aware of are that snapshot jobs and their associated component templates are both maintained within BMC Server Automation as versioned objects, and that any update to anything associated with either type of object will trigger a rebaselining of the snapshot job. Rebaselining results in all configuration items collected by the job for all servers that the job has run against to be reloaded into the BMC Server Automation database, regardless of whether their associated values have changed since the last run of the job.
- Go to your Snapshot Job and re-execute it. Note how the Change Tracking window gets reset and you will see the message "New baseline has no Change Tracking information".
- If you make additional changes to the files on the server and then re-execute the Snapshot Job again, you'll see the results in the Change Tracking window.
- Click to view the differences between the master and the target.