PowerHA 7: How to Change the Order of IP Aliases

With PowerHA 7 the default behaviour to set IP addresses has changed. With PowerHA 6 and lower the persistent or boot address always is the first alias on an interface:

# /usr/es/sbin/cluster/utilities/halevel -s
6.1.0 SP12
# netstat -i
Name  Mtu   Network     Address            Ipkts  Ierrs    Opkts Oerrs  Coll
en0   1500  link#2      56.a8.96.46.d.ab 30595036     0 39045319     0     0
en0   1500  10.116.6    mylpar01p        30595036     0 39045319     0     0    <= persistent address on top
en0   1500  10.116.6    mylpar01         30595036     0 39045319     0     0
en1   1500  link#3      56.a8.96.46.d.11   429722     0   356329     0     0
en1   1500  192.168.4   mylpar01m         429722      0   356329     0     0
lo0   16896 link#1                        1018980     0  1018950     0     0
lo0   16896 127         loopback          1018980     0  1018950     0     0
lo0   16896 ::1%1                         1018980     0  1018950     0     0

But beginning with PowerHA 7.1 when you start a resource group the corresponding service address is set as first alias and appears on the top of the list with netstat -i:

# /usr/es/sbin/cluster/utilities/halevel -s
7.1.3 SP3
# netstat -i
Name  Mtu   Network     Address              Ipkts Ierrs    Opkts Oerrs  Coll
en0   1500  link#2      56.a8.96.46.d.ab  30595036     0 39045319     0     0
en0   1500  10.116.6    mylpar01          30595036     0 39045319     0     0
en0   1500  10.116.6    mylpar01p         30595036     0 39045319     0     0   <= persistent address on second position
en1   1500  link#3      56.a8.96.46.d.11    429722     0   356329     0     0
en1   1500  192.168.4   mylpar01m           429722     0   356329     0     0
lo0   16896 link#1                         1018980     0  1018950     0     0
lo0   16896 127         loopback           1018980     0  1018950     0     0
lo0   16896 ::1%1                          1018980     0  1018950     0     0

Not a big deal you might think but outgoing packages are now marked with the service address. To avoid problems with firewalls when migrating to PowerHA 6 you might want to restore the old behaviour. This can be done by changing the parameter "RESOURCE_DIST_PREF" from "AC" to "NOALI":

# export PATH=$PATH:/usr/es/sbin/cluster/utilities
# clmgr query networks
net_ether_01
net_ether_02
# clmgr query network net_ether_01 | grep RESOURCE_DIST_PREF
RESOURCE_DIST_PREF="AC"
# clmgr modify network net_ether_01 RESOURCE_DIST_PREF=NOALI
# clmgr query network net_ether_01 | grep RESOURCE_DIST_PREF
RESOURCE_DIST_PREF="NOALI"

After restarting the cluster the persistent address appears on the top of the list again:

# /usr/es/sbin/cluster/utilities/halevel -s
7.1.3 SP3
# netstat -i
Name  Mtu   Network     Address               Ipkts Ierrs    Opkts Oerrs  Coll
en0   1500  link#2      56.a8.96.46.d.ab   30595036     0 39045319     0     0
en0   1500  10.116.6    mylpar01p          30595036     0 39045319     0     0   <= persistent address on top again
en0   1500  10.116.6    mylpar01           30595036     0 39045319     0     0
en1   1500  link#3      56.a8.96.46.d.11     429722     0   356329     0     0
en1   1500  192.168.4   mylpar01m            429722     0   356329     0     0
lo0   16896 link#1                          1018980     0  1018950     0     0
lo0   16896 127         loopback            1018980     0  1018950     0     0
lo0   16896 ::1%1                           1018980     0  1018950     0     0

For those who prefer SMIT:

# smitty sysmirror
    -> Cluster Applications and Resources 
       -> Ressources 
          -> Configure Service IP Labels/Addresses 
             -> Configure Service IP Labels/Address Distribution Preference 
                ->  net_ether_01
                   ->

                       Configure Service IP Labels/Address Distribution Preference

Type or select values in entry fields.
Press Enter AFTER making all desired changes.

                                                        [Entry Fields]
* Network Name                                        net_ether_01
* Distribution Preference                             Disable Firstalias          +
  Source IP Label for outgoing packets                                            +