## Overview
Detailed steps on adding new collector servers to a single-box system, and new collector servers to an existing Opsview Monitor system with multiple servers and existing collectors.
## Prerequisites before adding collectors:
A deployment host running a supported [Operating System](🔗) by the version of Opsview
Root access to the deployment host
SSH access from the deployment host to all Opsview hosts (including new servers to be added as collector hosts)
Authentication must use SSH public keys
The remote user must be 'root' or have 'sudo' access without a password and without TTY
## Adding Collector Servers
### To a Single Server System
To add new collector servers to an existing single-server Opsview Monitor system, open the `/opt/opsview/deploy/etc/opsview_deploy.yml
` file, and add the following lines.
**Note:** Do not change the existing lines in opsview_deploy.yml:
Change "opsview-de-1" and "10.12.0.9" to the hostname and IP address of your new collector, and give your collector cluster a name by changing "collectors-de".
You may add multiple collector-clusters, and multiple collectors under each cluster such as:
Cluster Size
There should always be an odd number of nodes within a collector cluster: 1, 3, 5, etc. This is to help with resiliency and avoid split-brain issues. In an even number cluster, if half the nodes go down the other half will stop functioning as the cluster within opsview-datastore and opsview-messagequeue will have no quorum and so will not accept updates until the other cluster members are restored. We do not support clusters with only two collectors for the above reason.
In the example configuration above, two new collector clusters called "collectors-de" and "collectors-fr" are created.
"collectors-de" has the minimum requirement of 3 collector nodes, while "collectors-fr" has 5 collector nodes, with hostnames and IP addresses provided.
After modifying opsview_deploy.yml, run opsview deploy as follows:
After running opsview-deploy, check "Registering New Collector Servers in Opsview Web" section.
### To a Multiple Server System
If you already have some collectors and you want to add new collectors, open `/opt/opsview/deploy/etc/opsview_deploy.yml
` on your deployment server (which is typically opsview host with orchestrator and opsview-web) and add new collector clusters or collector hosts after existing ones such as:
In the example above, 5 new collector hosts exist (new-host1, new-host2, new-host3, new-host4 and new-host5), and 1 new collector cluster (new-collector-cluster1) have been added.
new-host1 and 2 are added to the existing collector cluster (existing-collector1)
new-host3, 4 and 5 are added to the new collector cluster (new-collector-cluster1).
After modifying opsview_deploy.yml, run opsview deploy as follows:
If you wish to speed up this process you may specify the collector cluster you are updating or creating. The best way to do this is to specify the collector cluster using the minus lowercase "-l" (l for Lima) option
this is a measure really sided with updating a collector cluster, to ensure the opsview-messagequeue configuration is correct
the below utilises the above cluster name of "existing-collector1", which is now "existing_collector1"
You may also use the collector names within double quotes if these are new collector clusters For a single new collector cluster (a cluster or one), you may use the collector name or names of the collectors
This is also best practice for removing a collector from a cluster.
## Collector variables
You may set specific component configuration against any Collector. Settings may be rolled out to individually or to all Collectors by utilising `/opt/opsview/deploy/etc/user_vars.yml
` and `/opt/opsview/deploy/etc/opsview_deploy.yml
`. In this example we shall look at setting specific examples against the `opsview-executor
` configuration for all collectors, then for the `existing-collector1
` server.
To push out the configuration against all collectors upon a deployment, you will need to have a "ov_component_overrides" section and an applicable component section specified such as "opsview_executor_config" - this is set within the `/opt/opsview/deploy/etc/user_vars.yml
`. These changes are applied to the components `<opsview-component>.yaml
` configuration file, so for the executor this is `/opt/opsview/executor/etc/executor.yaml
`. The below will change the system defaults for `initial_worker_count
` to 4 (a system default of 2) and `max_concurrent_processes
` to 10 (a system default of 25).
Then run a deployment using the 'setup_everything.yaml` playbook to push out this configuration to all Collectors.
If the configuration is only required on one collector then modify the `/opt/opsview/deploy/etc/opsview_deploy.yml
` to add the overrides into the `vars:
` section for specific collector, as follows:
Instead of running the whole Deploy process, use the `collector-install.yml
` playbook against the specific collector (as detailed in an above section). If multiple collectors within the same Cluster are modified, ensure you run the playbook against all of them at the same time by using the option `-l collector1,collector2.collector3
`.
## Registering New Collector Servers in Opsview Web
Log into your Opsview Monitor user interface and go to the Configuration > Monitoring Collectors page. You should see a yellow "Pending Registration" message at the right such as below:

Click the menu icon on the right side of the hostname of your collector and click Register as below:

another window to register the collector will appear:

Click "Submit Changes and Next". A new window will appear to create a "New Monitoring Cluster":

Give the new monitoring cluster the same name that you add to opsview_deploy.yml, such as "collectors-de". Select the collectors that should be in this monitoring cluster from the list of collectors, then click Submit Changes.
After adding the first monitoring cluster, you may register a collector in an existing monitoring cluster by selecting "Existing Cluster", and selecting the monitoring cluster from the drop down list:

After registering your new collectors, you should see your clusters and the number of collectors under each cluster in the "Clusters" tab:

You can even click the numbers in "COLLECTORS" column to see the collector hostnames:

Once the new collectors are registered go to Configuration > Apply Changes, to place the collectors into production.
Confirm the Collectors are running correctly by checking the System Overview tab in Configuration > My System:

## Removing a Collector from a Cluster
To remove a Collector from a Cluster, click "CONFIGURATION > MONITORING COLLECTORS" from top menu and then click Clusters tab. Then, click menu icon and "Edit":

Then, deselect the Collector that you want to remove and click "Submit Changes" button. You can now go to Configuration > Apply Changes to confirm the change and shutdown the Collector.

## Adding a Collector to a Cluster
To add a Collector to a Cluster, edit the Cluster and then select the Collector (use Cntrl on Windows or Cmd on Mac OS to select in addition to the existing selections). Go to Configuration > Apply Changes to confirm the change.

## Deleting a Cluster
You may only delete clusters that are not monitoring any hosts. If you need to delete a cluster that has hosts assigned to be monitored, you must manually change the "monitored by" field for those hosts to another monitoring cluster. This can be done easily using the Bulk Edit tool within Configuration > Hosts.
You will need to go to Configuration > Apply Changes for this to take effect.
## Deleting a Collector
If you need to decommission a Collector, you must do the following:
Remove the Collector from any Clusters before attempting to delete it. You can remove Collectors from Clusters in the Clusters tab. If the Cluster only contains a single Collector, disable the Collector, then delete the cluster.
Delete the Collector record. Deleting a collector will remove it from the list of known Collectors. You can delete collectors from Collectors tab in Configuration > Monitoring Collectors page.
Delete the associated Host record in Host settings in order to completely remove it from Opsview.
**Note:** If you have deleted a Collector but then you want to register it again, you will not see it become available in the Unregistered Collectors grid until you stop the Scheduler on that collector for at least a whole minute and then restart it.
## Upgrading a Collector
Upgrading Collector is as simple as upgrading all Opsview packages on the Collector Server. To avoid any downtime shut down the connection from Collector to Master MessageQueue Server, upgrade all packages and reset the system. Once the connection is restored the Collector will automatically join the Cluster and you can now perform upgrade of the other Collectors.
## Managing Collector Plugins
In a distributed Opsview Monitor system, monitoring scripts on the Collectors may become out of sync with the ones on the Orchestrator when:
new Opspacks, monitoring scripts or plugins have been imported to Orchestrator.
monitoring scripts have been updated directly on Orchestrator.
In such cases, the monitoring scripts folder (`/opt/opsview/monitoringscripts
`) on the Orchestrator needs to be synced to all of the Collectors by using an ansible playbook called `sync_monitoringscripts.yml
`.
### Overview
The `sync_monitoringscripts.yml
` playbook uses `rsync
` to send appropriate updates to each Collector (it will be installed automatically if required) while excluding specific sets of files.
The following directories and files (relative to `/opt/opsview/monitoringscripts
`) are not synced:
For example, using the above exclude list, files within the `/opt/opsview/monitoringscripts/lib/
` directory and specific files such as `/opt/opsview/monitoringscripts/etc/notificationmethodvariables.cfg
` won't be synced.
Additionally, if the Collector does not have the same OS version as the Orchestrator, only statically linked executable files and text-based files will be synced. This is to ensure binaries used on the Orchestrator are not synced with an incompatible Collector. For example, an AMD64 binary will not be sent to an ARM32 based Collector.
Interpreted script files such as Python, Perl and Bash scripts and configurations files are all text-based files and _will_ be synced.
Dynamically linked executable files _will not_ be synced because they may not run properly due to runtime dependencies. Such dynamically linked executable files need to be installed on collectors manually if collectors have a different OS version than the Orchestrator.
### Prerequisites
SSH keys are setup between the Orchestrator and collectors (this should already be in place if Opsview Deploy was previously used to install or update the system).
### How to Sync
Run the following commands as root on the Orchestrator:
### Limitations
If your deploy server is not Orchestrator, you can run the same commands on your deploy server but SSH keys must have been setup between the Orchestrator and collectors for the SSH users defined for your collectors in your opsview_deploy.yml file.