About DCO cluster environments
To achieve high availability, you can run DCO in a clustered environment with two servers. This means your system will still be available if one server crashes since it will continue to run on the other server.
To minimize the risk of data loss, you can add an offsite disaster recovery node.
Supported DCO setups:
- 1 standalone node
- 1 standalone node + 1 DR node (requires 1 high availability license)
- 2 cluster nodes (requires 1 high availability license)
- 2 cluster nodes + 1 DR node (requires 2 high availability licenses)
When running DCO in a clustered environment, additional nodes in the cluster or a disaster recovery node (besides the initial DCO server) requires a high availability license as illustrated above.
For security reasons:
- Ensure your DCO cluster nodes are protected from direct Internet access by a proxy server.
See how to configure a proxy in the DMZ between the Internet and DCO in the Web proxy server setup guide.
- Ensure your DCO desktop client cannot be accessed from the Internet either. It should only be available on your intranet.
Running StruxureWare Data Center Operation in a clustered environment requires low network latency. Therefore, the clustered servers should be installed in the same data center site and on the same network subnet. All cluster nodes must have a static IP address. If your setup includes a disaster recovery node, you can have a firewall between the cluster and the disaster recovery node. See here for details about network ports.
Your network must support VRRP (Virtual Router Redundancy Protocol). If your network does not meet this requirement, use a disaster recovery setup rather than using a clustered environment.
Setting up a DCO cluster
You configure cluster setup in the Webmin server configuration interface. When configured, the cluster appears as a single
server to the user. During configuration, you add each node individually and specify that the server is a participant in the cluster.
Ensure you have an IP to use as cluster Virtual IP (VIP) on the same subnet as your DCO servers. E.g.:
Server 1: xxx.xxx.xxx.121 (netmask: 255.255.255.0)
Server 2: xxx.xxx.xxx.122 (netmask: 255.255.255.0)
VIP: xxx.xxx.xxx .123
Configuring the first (primary) node
- Install StruxureWare Data Center Operation with cluster configuration. See how.
- Open the Webmin web interface by selecting Administration>Webmin in the DCO web client.
Alternatively, type the address of your DCO server in a Web browser using https on port 10000:
- Accept self-signed certificate (in Your connection is not private, click to Proceed to the IP (unsafe)).
- Log into Webmin using the credentials created during the installation (Linux OS admin user) and navigate to StruxureWare DC Operation.
- In Setup, select Setup new cluster and enter an IP address that is reserved on your network to be used as virtual address of the cluster.
This is the IP address that will serve as the common entry point to the cluster.
It must be a proper IP address and it must not be used by any other entities on the network.
- Configure system time synchronization (NTP).
Note: Correct time settings are crucial for cluster nodes. Ensure you configure this during installation. Recommendation: Synchronize the time on all nodes with the same NTP server(s).
The default NTP servers are fine if there is an Internet connection. If the Data Center Operation servers are on a closed network, you should add a local NTP server. You must configure time synchronization separately on each node.
- For improved security, specify a range of IP addresses allowed to administrate the cluster (Webmin allowed IP addresses).
For more information about security related settings, see StruxureWare Data Center Operation security.
The default values for the other options should be fine, unless you have a special network setup.
- Click Setup and wait for the Application to start up before continuing to the next node. You can verify that the application has started up on the node in Webmin StruxureWare DC Operation>Status (Application Status should be Running).
TIP: Configuring the node takes time.
Configuring the additional node
Prerequisite: You have configured the first (primary) node.
- On the first node's configuration interface, specify that the additional node is allowed to join the cluster.
- Open the Webmin server interface on the first node and navigate to StruxureWare DC Operation.
- In Cluster Participants, enter the IP address of the new additional node and specify that it is allowed to join the cluster.
- Accept the fingerprint of the additional node.
- On the additional node's configuration interface, specify which cluster to join.
- Switch to the Webmin interface on the new node by clicking the Webmin link or typing the IP address in the browser address line and navigate to StruxureWare DC Operation>Cluster Participants.
- Specify the virtual IP address of the cluster the additional node should join and verify the cluster's fingerprint.
The node will copy all the settings from the first node.
- Click Setup and wait for the Application to start up. You can verify that the application has started up on the node in Webmin StruxureWare DC Operation>Status (Application Status should be Running).
- Set the NTP address(es) on the second node: StruxureWare DC Operation>Setup. Type in the same NTP Servers as you used on the first server. Click the Update button just below the NTP settings.
Verifying the cluster setup
- Open the Webmin server interface on one of the nodes.
- In StruxureWare DC Operation>Cluster Participants, verify that the cluster setup includes the correct nodes.
- In StruxureWare DC Operation>Status, verify that the nodes are running (especially that Application State is Running).
The cluster environment has now been set up. Clients will connect to the virtual IP address of the cluster, not the nodes. You can continue to install the licenses.
To configure a stand-alone disaster recovery node for extra security, see here.
Configuring NTP servers for both nodes after setting up the cluster
If you are using a non-default NTP server, setup the same NTP server or servers for both nodes after setting up the cluster to ensure they both use the same NTP server or servers.
- Open Webmin on one of the servers as described above.
- Select StruxureWare DC Operation>Setup.
- In NTP Settings set the IP of the NTP server you want to use, and click Update.
If using multiple NTP servers, enter NTP servers on separate lines.
- Wait for the setup to finish and verify that Webmin on both node servers show the same NTP server or servers.