You are currently reviewing an older revision of this page.
The purpose of this article is to provide an understanding of how VM Migration Software, such as VMware VMotion, works and answers to some of the common questions related to using those software with Appian.
Live migration refers to the process of moving a running virtual machine or application between different physical machines without disconnecting the client or application. Memory, storage, and network connectivity of the virtual machine are transferred from the original guest machine to the destination. There are many software use to complete this process, one commonly used is VMware VMotion.
Appian does not recommend running any live VM migration software in your Appian environment because their capability has been known to cause corruption inside Zookeeper. This can lead to site unavailability. Appian recommends disabling VMotion for any VMware severs that host Zookeeper. Appian's stance on this is:
"Zookeeper is very sensitive to latency. This is by design, since Zookeeper is in charge of coordinating state across the cluster. The migration process creates enough of a communications gap between the Zookeeper instances that they think a failure has occurred. Ephemeral data inside Zookeeper can be lost and if multiple Zookeeper nodes are migrated at the same time then they can lose quorum, which will cause that data to be lost. In addition, this blip in the Zookeeper cluster will almost assuredly cause Kafka/Service Manager to engage failover mechanism."
This article applies to Appian 17.3 and later.
Last Reviewed: April 2019