Moving to Crowd Data Center
Below is the process for migrating from Crowd Server to Crowd Data Center.
If you're installing Crowd for the first time and you don't have any existing Crowd data to migrate, see Installing Crowd Data Center.
Before you begin
Before you install Crowd Data Center, you need to answer a few questions.
What is Crowd Data Center?
|How do I get it?|
What are the prerequisites?
Tell me more...
Supported operating systems, databases, etc., are the same as for the Server installation, and you can see them here: Supported platforms. You need to use an external database - HSQLDB is not supported.
Those specific to Data Center include requirements for nodes that create the cluster:
|Do I need a load balancer?||
Tell me more...
Yes. Crowd Data Center relies on a load balancer to balance the traffic between the nodes, and this guide assumes that you already have one set up. You can use a load balancer of your choice, just make sure it meets these requirements:
Or you can just turn your proxy into a load balancer.
Many bigger installations of Crowd already have a reverse proxy configured, and many reverse proxies can do load balancing as well. We've provided some examples on how to use your proxy as a load balancer. See Load balancer examples.
1. Enable Crowd Data Center on your existing Crowd Server instance
Crowd Data Center is available for Crowd 3.0, or later. If you're not on this version yet, install or upgrade your Crowd instance. See Crowd installation and upgrade guide.
- Go to > Licensing to enter your license key. Once successful you should see that Data Center is now available, but you need to restart before you can start using it:
Stop Crowd now. Before restarting it you will need to set up the shared home directory.
2. Set up the shared directory
Crowd Data Center requires that the <
CROWD HOME>/shared directory can be read and written by all the machines running Crowd Data Center.
When installing Crowd Server <
CROWD HOME>/shared is created as a normal directory. To use Crowd Data Center:
- Stop Crowd.
- Backup your Crowd home directory before making any changes.
Prepare a shared, network-accessible directory.
For this example we will assume the you are using Linux, and the shared directory is available at
<CROWD HOME>/sharedto the shared directory you've prepared:
mv <CROWD_HOME>/shared /mnt/nfs/crowd
Mount or create a symbolic link at
<CROWD_HOME>/sharedthat points to the copied directory:
ln -s /mnt/nfs/crowd/shared <CROWD_HOME>/shared
- Check if
<CROWD_HOME>/shared/crowd.cfg.xmlexists and is accessible from the machine running Crowd to verify you have configured the directory correctly.
- Start Crowd again.
3. Add the first Crowd node to your load balancer
The load balancer distributes the traffic between the nodes. If a node stops working, the remaining nodes will take over its workload, and your users won't even notice it.
- First, add your load balancer as a trusted proxy server in Crowd. See Configuring Trusted Proxy Servers.
Add the first node to the load balancer.
- Restart the node, and then try opening different pages in Crowd. If the load balancer is working properly, you should have no problems with accessing Crowd.
In Crowd, go to > Clustering. The node should be listed as part of the cluster.
If your load balancer supports health checks, configure it to perform a check on
<crowd-node>is the node's hostname or IP address, and
<context-path>is the Crowd's context path (e.g.
/crowd). If the node doesn't respond with a
200 OKresponse within a reasonable time, the load balancer shouldn't direct any traffic to this node.
- After you've added the node to the load balancer, configure the Crowd's base URL to also point to the load balancer. Go to > General, and enter the URL of your load balancer as Base URL.
4. Add the remaining nodes to the cluster
- Copy the Crowd installation directory to the new node.
- Create a home directory, like you did for the first node, and mount
sharedas its sub-directory.
crowd-init.properties, and enter the path to the home directory that you just created.Where can I find crowd-init.properties?
crowd-init.propertiesfile is in
- Go to
<installation-directory>/apache-tomcat/conf/Catalina/localhost, and delete the
openidserver.xmlfile. This is needed because currently the CrowdID component doesn't support clustering, and it must be enabled only on the first node. The component will work as usual.
- Start Crowd. It will read the configuration from the shared directory, and start without any extra setup.
- Take a look around the new Crowd instance. Verify that user and group management, directory synchronization, and any custom integrations all work as expected.
- Again, verify that the node was added to the cluster. In Crowd, go to > Clustering.
If everything looks fine, you can configure your load balancer to start routing traffic to the new node. Once you do this, you can make a couple of changes in one Crowd instance to see if they're visible in other instances as well.
Adding node names
When displaying information about your nodes in the Crowd footer or on the > Clustering page, Crowd Data Center uses random IDs that were generated for your nodes. Instead, you can give them more persistent and readable names by setting the
cluster.node.name system property, like in the following example: