Troubleshooting Cluster Replication Problems - Cisco TelePresence Video Communication Server Administrator's Manual

DNS servers are not replicated across peers - each peer can use a different set of DNS servers.
However, the DNS domain name is replicated across peers.
Logging
The Event Log and Configuration Log on each peer will only report activity for that particular VCS. You
are recommended to set up a remote syslog server to which the logs of all peers can be sent. This will
allow you to have a global view of activity across all peers in the cluster. See the
further details.
Conference Factory template
The template used by the
as it must be unique for each peer in the cluster.
CA certificates
The security certificates and certificate revocation lists (CRLs) used by the VCS must be uploaded
individually per peer.
Note: configuration data that is replicated across peers should not be modified on non-master peers.
At best it will result in the changes being overwritten from the master; at worst it will cause cluster
replication to fail.

Troubleshooting cluster replication problems

Cluster replication can fail for a variety of reasons. The most common problems are listed below,
followed by instructions for resolving the problem:
NTP servers not configured and active on each cluster peer
1. For each peer in the cluster, go to the
2. Ensure the peer has a correctly configured and active NTP server.
Some peers have a different master peer defined
1. For each peer in the cluster, go to the
2. Ensure each peer identifies the same Configuration master.
Cluster configuration script has not been run against each peer
1. For each peer in the cluster, go to the
2. Enter the address of each of peer into the Peer IP address fields and configure the Configuration
master. Ensure each peer identifies the same Configuration master peer.
3. Log in to each peer as root (by default you can only do this using a serial connection or SSH) and
run the cluster configuration script. Full details on running this script and configuring clusters is
available in the Cluster creation and maintenance deployment guide [27].
Note that cluster replication warnings can appear briefly while the cluster is initially being set up.
These warnings are removed after the data has completed synchronizing and the cluster has
stabilized. This takes approximately 3 minutes.
Unable to reach the cluster configuration master peer
The VCS operating as the master peer could be unreachable for many reasons, including:
network access problems
n
VCS unit is powered down
n
incorrectly configured IP addresses
n
incorrectly configured IPsec keys - ensure each peer is configured with the same Cluster pre-
n
shared key value.
Cisco VCS Administrator Guide (X6.1)
Conference Factory application to route calls to the MCU is not replicated,
System > Time
VCS configuration > Clustering
VCS configuration > Clustering
logging
page.
page.
page.
Clustering and peers
section for
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