PartitionsA partition depicts the division in an IaaS and defines an area of an IaaS cloud used by a service subscription. A partition can be made at one of the following levels: Provider level, Region level, Zone level or Rack level. A partition should at least have a provider defined. If required, partition groups can be defined in the partition definition. DevOps, for the purpose of high availability, can define multiple partitions in order to instruct Apache Stratos to spawn instances in multiple areas (e.g., region, zone or rack). For example, if you spawn instances in multiple availability zones in EC2, your system will be still functional even if one availability zone is down.
A partition group is the an area of an IaaS that is bound by one network of an IaaS (e.g., region). Partition groups are also referred to as network partitions. We can include several partitions inside a network partition. Thereby, DevOps can define multiple partition groups, which have multiple partitions under it, for the purpose of high availability.
One after the other
When using this algorithm, instances will be spawned in the same partition until the maximum number of instances for the respective partition is reached, before spawning instances in the next partition. For example, if there are two partitions named P1 and P2, instances will be spawned in the same partition until the maximum number of instances are reached, before spawning instances in P2.
When using this algorithm, instances will be spawned in each of the partitions sequentially. For example, if there are two partitions named P1 and P2, after an instance is spawned in P1 it will spawn the next instance in P2.
one after the other. For example, if an enterprise has its private cloud, all instances would be allocated there, and when we run out of capacity, we would go to the next partition on the public cloud. The
round robincase could be a case for very high availability, where instances are spawned across multiple IaaS providers.
partitions.jsonfile in the registry. DevOps need to use the deployment policy to define the design of the partitions and partition groups (network partitions) used in their PaaS. Partitions are defined in WSO2 Private PaaS to manage the instance count. Thereby, when defining the deployment policy the maximum number of instances allowed in a partition per cartridge subscription (
partitionMax)and the minimum number of instances allowed in a partition per cartridge subscription (
partitionMin)needs to be specified. For information on the workflow, see Partition Deployment Workflow.