Symptoms
Ephemeral pool members might not be added to a pool with an FQDN pool member "autopopulate enabled".
When this issue occurs:
-- Some or all of the expected Ephemeral Pool Members will not be created for the affected pool.
-- A message will be logged in the LTM log similar to the following:
err mcpd[####]: 01070734:3: Configuration error: Cannot enable pool member to autopopulate: node (/Common/_auto_<IP address>) has autopopulate set to disabled.
(Note that the node name here is an Ephemeral Node.)
Also note that if you attempt to create an FQDN Pool Member with autopopulate enabled while the corresponding FQDN Node has autopopulate disabled, you will see a similar error message:
01070734:3: Configuration error: Cannot enable pool member to autopopulate: node (/Common/fred) has autopopulate set to disabled.
Impact
The affected LTM pool(s) are not populated with expected (or any) ephemeral pool members.
Conditions
This issue can occur under the following conditions:
-- Two or more FQDN Nodes have FQDN names that resolve to the same IP address(es).
-- That is, some Ephemeral Nodes have addresses resolved by more than one FQDN name defined in FQDN Nodes.
-- At least one of these FQDN Nodes has "autopopulate enabled."
-- At least one of these FQDN Nodes does not have "autopopulate enabled."
-- That is, autopopulate is disabled for one or more of these FQDN Nodes.
-- The FQDN Pool Member(s) in the affected pool(s) has "autopopulate enabled."
Workaround
To allow some LTM pools to use FQDN pool members with autopopulate enabled (allowing multiple ephemeral pool members to be created) while other LTM pools use FQDN pool members with autopopulate (allowing only one ephemeral pool member to be created), configure the following:
-- Create all FQDN Nodes with FQDN names that might resolve to a common/overlapping set of IP addresses with "autopopulate enabled".
-- Create FQDN Pool Members with autopopulate enabled or disabled depending on the desired membership for each pool.
Fix Information
Ephemeral pool members can now be successfully added to LTM pools regardless of the autopopulate configuration of the respective FQDN pool member.
