Creating a DPF Db2 Roving Standby HA instance on a Pacemaker-managed Linux cluster

Db2 12.1 provides a DPF high availability option for Db2 when deployed on a Pacemaker-managed Linux cluster. You create the cluster using the Db2 cluster manager (db2cm) utility.

About this task

Important: Starting from Db2® 12.1, DPF high availability is supported when using Pacemaker as the integrated cluster manager. The Pacemaker cluster manager is packaged and installed with Db2.

Db2 DPF is a highly available deployment where multiple cluster nodes have identical Db2 instance installations and a shared filesystem as the instance home directory. The partitions can be activated on any cluster nodes within the Pacemaker cluster. With this solution, the setup, configuration, and management of the deployment is handled with the db2cm utility, and the automation of the solution is monitored and controlled by the Pacemaker cluster manager.

The following placeholders are used in the command statements throughout this procedure. These represent values that you can change to suit your organization:

<host#> is the hostname for the DPF cluster nodes in the Db2 Linux cluster
<qdevice_host> is the host name of the quorum device, which is used to make cluster management decisions when Pacemaker cannot.
<partition_number> is a unique number that identifies the database partition server in the Db2 Pacemaker DPF cluster.
<database_name> is the name of the Db2 database.

Procedure

Create a Db2 home file system for a partitioned database environment. To install Db2 Enterprise Server Edition and create a partitioned database environment, you must have a file system that is available to all of the machines.
Verify that NFS is running (Linux and UNIX).Before setting up a database partitioned environment, you should verify that Network File System (NFS) is running on each computer that will participate in your partitioned database system.
Create groups and users in a partitioned database environment. To install the IBM® Db2 Enterprise Server Edition software and create a partitioned database environment, you must create users and groups to operate the Db2 databases.
Set up a partitioned database environment. This topic describes how to set up a partitioned database environment. You will use the Db2 Setup wizard to install your instance-owning database server and to create the response files that will in turn be used to create your participating database servers.
Take the first steps after the Db2 Partitioned Database Environment installation.After you install a partitioned database environment, you must perform additional tasks and can optionally perform other tasks.
Verify the installation. You should verify that your Db2 database server installation was successful.
Determine the DPF hosts that will be used as standby hosts. Modify db2nodes.cfg so no partitions are defined to run on standby hosts.
Start Db2 as an instance user by runningdb2start
Configure DPF roving standby with db2cm:
1. On the first host, go to /<db2_fs_dir>/<db2_home_dir>/sqllib/bin/ and locate the db2cm.
2. Run db2cm to create your Db2 domain as a system administrator user:
```
[root@<host1>]# db2cm -create -domain <domain_name> -standbyhostlist <host4>,<host5>
```
3. Confirm the domain is created correctly by running:
```
[root@<host1>]# db2cm -list
```
4. After confirming that the domain is created correctly, create a partition resource by running:
```
[root@<host1>]# db2cm -create -resources
```
5. Confirm partition resources are correctly created by running:
```
 [root@<host1>]# db2cm -list
```
6. Optional: For any existing databases, add and associate database mount resources with an existing Pacemaker cluster:
```
db2cm -add -dbMount -db <database_name> 
```
  Running this command creates database mount resources for the database directories if they do not already exist.
7. Create a VIP resource on the partition:
```
 [root@<host1>]# db2cm -create -primaryVIP <virtual IP address> -partition <partition_number>
```
8. Optional: Create a Quorum Device if the number of total nodes is even:
```
[root@<host1>]# db2cm -create -qdevice <qdevice_host>
```
9. Verify the configuration of your DPF, Pacemaker-managed Db2 cluster:
```
[root@<host1>]# db2cm -list
```

Example

The following example shows the output from running the db2cm -list command to verify the creation of a Db2 Pacemaker DPF Roving Standby HA cluster ( see Step 9.)


$ db2cm -list

HA Model: DPF Roving Standby

Domain Information:
Domain name                     = hadomain
Cluster Manager                 = Corosync
  Cluster Manager Version       = 3.1.7
Resource Manager                = Pacemaker
  Resource Manager Version      = 2.1.6-4.db2pcmk.el9
Current domain leader           = dpf-srv-1
Number of nodes                 = 4
Number of resources             = 4

Host Information:
HOSTNAME                        STATE           MAXIMUM PARTITIONS              NUMBER OF PARTITIONS
------------------------        --------        ------------------------        --------------------------
dpf-srv-1                       ONLINE          2                               2
dpf-srv-2                       ONLINE          2                               2
dpf-srv-3                       ONLINE          2                               2
dpf-srv-4                       ONLINE          2                               0

Fencing Information:
Fencing Configured: Not configured

Quorum Information:
Quorum Type: Majority
Total Votes: 4
Quorum Votes: 3
Quorum Nodes:
----------------
dpf-srv-1
dpf-srv-2
dpf-srv-3
dpf-srv-4

Resource Information:
Resource Name             = db2_ethmonitor_dpf-srv-1_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-1
    Interface Name              = eth0

Resource Name             = db2_ethmonitor_dpf-srv-2_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-2
    Interface Name              = eth0

Resource Name             = db2_ethmonitor_dpf-srv-3_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-3
    Interface Name              = eth0

Resource Name             = db2_ethmonitor_dpf-srv-4_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-4
    Interface Name              = eth0

The following example shows the output from running the db2cm -list command to verify the 3 active nodes and 1 standby node Pacemaker DPF Roving Standby HA cluster ( see Step 9.i )


$ db2cm -list

HA Model: DPF Roving Standby

Domain Information:
Domain name                     = hadomain
Cluster Manager                 = Corosync
  Cluster Manager Version       = 3.1.7
Resource Manager                = Pacemaker
  Resource Manager Version      = 2.1.6-4.db2pcmk.el9
Current domain leader           = dpf-srv-1
Number of nodes                 = 4
Number of resources             = 17

Host Information:
HOSTNAME                        STATE           MAXIMUM PARTITIONS              NUMBER OF PARTITIONS
------------------------        --------        ------------------------        --------------------------
dpf-srv-1                       ONLINE          2                               2
dpf-srv-2                       ONLINE          2                               2
dpf-srv-3                       ONLINE          2                               2
dpf-srv-4                       ONLINE          2                               0

Fencing Information:
Fencing Configured: Configured
Fencing Devices:
----------------
watchdog

Quorum Information:
Quorum Type: Qdevice with FFSplit Algorithm
Total Votes: 5
Quorum Votes: 3
Quorum Nodes:
----------------
dpf-srv-1
dpf-srv-2
dpf-srv-3
dpf-srv-4

Resource Information:
Resource Name             = db2_ethmonitor_dpf-srv-1_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-1
    Interface Name              = eth0

Resource Name             = db2_ethmonitor_dpf-srv-2_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-2
    Interface Name              = eth0

Resource Name             = db2_ethmonitor_dpf-srv-3_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-3
    Interface Name              = eth0

Resource Name             = db2_ethmonitor_dpf-srv-4_eth0
  State                         = Online
  Managed                       = True
  Resource Type                 = Network Interface
    Node                        = dpf-srv-4
    Interface Name              = eth0

Resource Name             = db2_partition_db2inst1_0
  State                         = Online
  Managed                       = True
  Resource Type                 = Partition
    Instance                    = db2inst1
    Partition Number            = 0
  Current Host                  = dpf-srv-1

    Resource Name             = db2_VIP_db2_partition_db2inst1_0_10.11.221.222
      State                         = Online
      Managed                       = True
      Resource Type                 = IP
        Instance                    = db2inst1
        Partition Number            = 0
        Ip Address                  = 10.11.221.222
      Current Host                  = dpf-srv-1

Resource Name             = db2_partition_db2inst1_1
  State                         = Online
  Managed                       = True
  Resource Type                 = Partition
    Instance                    = db2inst1
    Partition Number            = 1
  Current Host                  = dpf-srv-1

Resource Name             = db2_partition_db2inst1_2
  State                         = Online
  Managed                       = True
  Resource Type                 = Partition
    Instance                    = db2inst1
    Partition Number            = 2
  Current Host                  = dpf-srv-2

Resource Name             = db2_partition_db2inst1_3
  State                         = Online
  Managed                       = True
  Resource Type                 = Partition
    Instance                    = db2inst1
    Partition Number            = 3
  Current Host                  = dpf-srv-2

Resource Name             = db2_partition_db2inst1_4
  State                         = Online
  Managed                       = True
  Resource Type                 = Partition
    Instance                    = db2inst1
    Partition Number            = 4
  Current Host                  = dpf-srv-3

Resource Name             = db2_partition_db2inst1_5
  State                         = Online
  Managed                       = True
  Resource Type                 = Partition
    Instance                    = db2inst1
    Partition Number            = 5
  Current Host                  = dpf-srv-3