Network Deployment (Distributed operating systems), v8.0 > Establishing high availability
Set up a high availability environment
The high availability framework provided with the product eliminates single points of failure and provides peer to peer failover for applications and processes running within the product environment. This infrastructure is managed by a high availability manager and includes cells, clusters, core groups, and high availability groups. Every high availability group has a policy associated with it that the high availability manager uses to determine which members of a high availability group are active at a given time.
Plan out how set up your high availability environment to avoid the risk of a failure without failover coverage. As part of the planning process, understand how the high availability manager can assist you in controlling this type of environment.
The high availability manager is designed to function in all of the supported product topologies. However, a high availability-managed environment must comply with the following rules:
- A cell in a high availability infrastructure is partitioned into one or more core groups. The product provides a default core group as part of the high availability manager function. We can use the admin console to create additional core groups.
- A core group cannot extend beyond the boundaries of a cell, and it cannot overlap with any other core groups.
- A cluster must be a member of only one core group. All of the individual members of that cluster must be members of the same core group.
- Individual application servers are also members of a core group.
- All running members of a core group must be able to communicate with all of the other running members of that same core group.
While administering your core groups, you might need to perform one or more of the following tasks. These tasks can be performed in any order.
- Enable the high availability manager if it is not already enabled.
- View information about the high availability groups, core groups, and core group members.
- Create a new policy and associate it with a high availability group.
- Change the policy that is associated with a high availability group.
- Create a new core group.
- Change the configuration settings for a core group.
While running the applications in a highly available environment, you might want to move core group members to a different core group. You also might want to change one or more of the following:
- The servers that designated as preferred coordinators.
- The number of core group coordinators.
- The settings for the discovery protocol, or the failure detection protocol. You might also want to change the version of the protocol.
- The replication settings for a core group.
- Configure a transport for a core group.
If you are using an IIOP transport, you might also need to complete one or more of the following actions:
- Specify a core group when you add a node.
- Specify a core group when you create an application server.
- Set up a core group bridge.
If you are using multiple core groups and members of different groups need to communicate with each other, set up a core group bridge to enable this communication.
What to do next
After you set up your product environment to comply with all of the high availability-managed environment rules, use the default core group to control this environment. Do not add core groups unless you cannot properly perform without them. Also, do not change the default configurations unless doing so provides the solution to a specific problem. When you do make configuration changes, such as changing the policy for a high availability group or moving core group members between core groups, make sure you fully understand the effect such changes have on your entire environment. Such changes might affect application processing.
Read the topic High availability environment troubleshooting tips if you encounter problems while running applications in your high availability environment.
High availability manager
Disable or enabling a high availability manager
View high availability group information
Create a policy for a high availability group
Select the policy for a high availability group
Create a new core group (high availability domain)
View the core groups in a cell
Move core group members
Configure core group preferred coordinators
Change the number of core group coordinators
Configure the default Discovery Protocol for a core group
Configure the default Failure Detection Protocol for a core group
Select the version of a core group protocol
Configure core group memory utilization
Configure a core group transport
Configure core group IP caching
Configure core group socket buffers
Specify a core group when adding a node
Specify a core group when creating an application server
View core group members
Set up IP addresses for high availability manager communications
Specify a preferred server for messaging requests
Configure the core group bridge service
High availability environment troubleshooting tips