In this post Ill demonstrate how to create a Cluster Aware AIX (CAA) cluster on AIX 7.1. Ill create a simple two-node CAA cluster. Ill then check the cluster status and, finally, remove the cluster.

Before I start, I make sure that both nodes have entries in /etc/hosts on both systems.

node1[/] > grep node /etc/hosts

172.29.134.169 node1

172.29.152.160 node2

node2[/] > grep node /etc/hosts

172.29.134.169 node1

172.29.152.160 node2

I verify that cluster services are not active on both nodes.

node1[/tmp/cg] > lscluster -i

Cluster services are not active.

node2[/] > lscluster -i

Cluster services are not active.

Ill now create a cluster named mycluster. My CAA repository disk is named hdisk1.

node1[/] > mkcluster -n mycluster -m node1,node2 -r hdisk1

My two node CAA cluster is now operational.

node1[/] > lscluster -c

Cluster query for cluster mycluster returns:

Cluster uuid: 2a476f06-be50-11e0-9781-66da93d16b18

Number of nodes in cluster = 2

Cluster id for node node2 is 1

Primary IP address for node node2 is 172.29.152.160

Cluster id for node node1 is 2

Primary IP address for node node1 is 172.29.134.169

Number of disks in cluster = 0

Multicast address for cluster is 228.29.134.169

I can immediately execute commands on both nodes using the clcmd utility.

node1[/] > clcmd uptime

-------------------------------

NODE node1

-------------------------------

11:16PM up 1:16, 1 user, load average: 1.10, 1.18, 1.36

-------------------------------

NODE node2

-------------------------------

11:16PM up 45 mins, 1 user, load average: 0.97, 0.75, 0.64

Prior to cluster creation, the disks on my system were named as follows:

node1[/] > lspv

hdisk1 00f6048892b78f9f None

hdisk0 00f6050a2cd79ef8 rootvg active

After cluster creation, hdisk1 is renamed to caa_private0 and is assigned to the CAA repository volume group named caavg_private.

node1[/] > lspv

caa_private0 00f6048892b78f9f caavg_private active

hdisk0 00f6050a2cd79ef8 rootvg active

node1[/] > lsvg caavg_private

VOLUME GROUP: caavg_private VG IDENTIFIER: 00f6048800004c0000000131930c1af3

VG STATE: active PP SIZE: 64 megabyte(s)

VG PERMISSION: read/write TOTAL PPs: 799 (51136 megabytes)

MAX LVs: 256 FREE PPs: 784 (50176 megabytes)

LVs: 6 USED PPs: 15 (960 megabytes)

OPEN LVs: 2 QUORUM: 2 (Enabled)

TOTAL PVs: 1 VG DESCRIPTORS: 2

STALE PVs: 0 STALE PPs: 0

ACTIVE PVs: 1 AUTO ON: yes

MAX PPs per VG: 32512

MAX PPs per PV: 1016 MAX PVs: 32

LTG size (Dynamic): 256 kilobyte(s) AUTO SYNC: no

HOT SPARE: no BB POLICY: relocatable

PV RESTRICTION: none

node1[/] > lsvg -l caavg_private

caavg_private:

LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINT

caalv_private1 boot 1 1 1 closed/syncd N/A

caalv_private2 boot 1 1 1 closed/syncd N/A

caalv_private3 boot 4 4 1 open/syncd N/A

fslv00 jfs2 4 4 1 open/syncd /clrepos_private1

fslv01 jfs2 4 4 1 closed/syncd /clrepos_private2

powerha_crlv boot 1 1 1 closed/syncd N/A

node1[/tmp/cg] > df -g

Filesystem GB blocks Free %Used Iused %Iused Mounted on

/dev/hd4 0.25 0.07 74% 10118 37% /

/dev/hd2 2.50 0.19 93% 45192 48% /usr

/dev/hd9var 0.38 0.02 95% 5995 47% /var

/dev/hd3 0.50 0.38 24% 187 1% /tmp

/dev/hd1 0.12 0.12 1% 11 1% /home

/dev/hd11admin 0.12 0.12 1% 5 1% /admin

/proc - - - - - /proc

/dev/hd10opt 0.38 0.13 65% 8021 21% /opt

/dev/livedump 0.25 0.25 1% 4 1% /var/adm/ras/livedump

/aha - - - 37 1% /aha

/dev/fslv00 0.25 0.25 2% 15 1% /clrepos_private1

Several services are started during cluster creation. In particular you will notice the following subsystems active (lssrc a output).

cld caa 7340104 active

solidhac caa 8912986 active

solid caa 8519794 active

clconfd caa 9306188 active

cthags cthags 9830450 active

ctrmc rsct 3342554 active

IBM.DRM rsct_rm 8716462 active

IBM.ServiceRM rsct_rm 9240724 active

IBM.StorageRM rsct_rm 8061146 active

IBM.MgmtDomainRM rsct_rm 8454200 active

node1[/tmp/cg] > lssrc -g caa

Subsystem Group PID Status

clcomd caa 6553810 active

cld caa 6619252 active

solidhac caa 8650856 active

solid caa 8781824 active

clconfd caa 10092598 active

Now I will remove the cluster.

node1[/] > rmcluster -n mycluster

rmcluster: Removed cluster shared disks are automatically renamed to names such

as hdisk10, [hdisk11, ...] on all cluster nodes. However, this cannot

take place while a disk is busy or on a node which is down or not

reachable. If any disks cannot be renamed now, you must manually

rename them by removing them from the ODM database and then running

the cfgmgr command to recreate them with default names. For example:

rmdev -l cldisk1 -d

rmdev -l cldisk2 -d

cfgmgr

CAA cluster services are no longer active.

node1[/] > lscluster -c

Cluster services are not active.

And caa_private0 is renamed back to hdisk1 and the caavg_private volume group is removed also.

node1[/] > lspv

hdisk1 00f6048892b78f9f None

hdisk0 00f6050a2cd79ef8 rootvg active

node1[/] > df

Filesystem 512-blocks Free %Used Iused %Iused Mounted on

/dev/hd4 524288 139136 74% 10097 37% /

/dev/hd2 5242880 405088 93% 45192 48% /usr

/dev/hd9var 786432 88040 89% 5986 35% /var

/dev/hd3 1048576 806528 24% 186 1% /tmp

/dev/hd1 262144 261352 1% 11 1% /home

/dev/hd11admin 262144 261416 1% 5 1% /admin

/proc - - - - - /proc

/dev/hd10opt 786432 279912 65% 8021 21% /opt

/dev/livedump 524288 523552 1% 4 1% /var/adm/ras/livedump

/aha - - - 32 1% /aha

node1[/] >