ivandika3 opened a new pull request, #4922: URL: https://github.com/apache/ozone/pull/4922
## What changes were proposed in this pull request? Currently, OM passes OzoneManager#getOmNodeId as the owner argument in OMKeyRequest#allocateBlock. This means that the created container's owner is based on the OM HA leader's Node ID specified in the ozone configuration (i.e. ozone.om.node.id). In the case where there are multiple OMs using the same SCM. If the Node IDs configured are not unique across the SCM cluster, there might be a situation where a single container contains blocks owned by multiple OMs. This should be fine for now, but in the future if we want to separate the containers based on the Storage Type, this collision might raise tricky situations For example for configuration (omitting om addresses) ``` <property> <name>ozone.om.service.ids</name> <value>service1,service2</value> </property> <property> <name>ozone.om.nodes.service1</name> <value>om1,om2,om3</value> </property> <property> <name>ozone.om.nodes.service2</name> <value>om1,om2,om3</value> </property> ``` If the OM leader of both service1 and service2 has the same node ID (e.g. om1), both OM will use the configured node ID as the owner when allocating block, and SCM will assume that the request comes from the same owner and allocate the same container for the blocks. We should find a way to pick a unique ID to pass to the allocateBlock call. Currently a valid option is to use omUuid since the chance of collisions would be smaller. However, a better option for the container owner is to pick a unique ID for the a single OM HA service (instead of node ID). This has possible additional advantages: When the OM leader change, the SCM does not need to create a new container for the new blocks Fewer number of OPEN containers and all containers in SCM overall Unfortunately, I have not found such an ID available. The candidates I have considered: OM's ClusterID is tied to the SCM so it doesn't make sense to use it as container owner. Service ID cannot be used since there doesn't seem to be any uniqueness guarantee across OM HA services. OM Service Ratis Group ID is also derived from the MD5 hash of OM HA Service ID so it cannot be used. Another consideration is to migrate the existing containers's owner to the new naming conventions. This might be able to be done by using some container task. This issue can be handled in another ticket. Any further suggestions are greatly appreciated. ## What is the link to the Apache JIRA https://issues.apache.org/jira/browse/HDDS-8874 ## How was this patch tested? Existing unit tests. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
