Heartbeat Clustering Interview Questions & Answers
Q: – What is Heartbeat HA ?
Heartbeat provides the basic functions required by any HA system such as starting and stopping resources, monitoring the availability of the systems in the cluster, and transferring ownership of a shared IP address between nodes in the cluster. Heartbeat is a software solution that monitors the health of a particular service (or services) through either a serial line or Ethernet interface or both. It is a vital component of the whole Linux-HA package.
Q: – What is DRBD ?
DRBD stands for Distributed Remote Block Device which is produced by LinBit Information Technologies GmbH, provides data mirroring between two servers on a LAN or WAN.DRBD currently supports one to one replication (i.e. two node clusters, where one node acts as a standby). It is anticipated that DRBD will support one to many replication in the near future. DRBD can be used to provide data replication between nodes for nearly any application (E.g. Apache, Samba, NFS, Oracle and so on), as well as being used as just an offsite data backup.
Q: – How to start and stop drbd service in linux ?
service drbd start
service drbd stop
Q: – What are the configurations files of Heartbeat cluster ?
/etc/ha.d/ha.cf the global cluster configuration file.
/etc/ha.d/authkeys a file containing keys for mutual node authentication.
Q: – What are the contents of authkeys file in heartbeat cluster ?
etc/ha.d/authkeys contains pre-shared secrets used for mutual cluster node authentication. It should only be readable by root and follows this format:
<num> <algorithm> <secret>
num is a simple key index, starting with 1. Usually, you will only have one key in your authkeys file. algorithm is the signature algorithm being used. We may use either md5 or sha1; the use of crc (a simple cyclic redundancy check, not secure) is not recommended. secret is the actual authentication key.
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