1. Validating¶

Before performing any operations with OpenStack environment, Sahara validatesuser input.

There are two types of validations, that are done:

• Check that a request contains all necessary fields and that the request doesnot violate any constraints like unique naming, etc.
• Plugin check (optional). The provisioning Plugin may also perform anyspecific checks like a Cluster topology validation check.

If any of the validations fails during creating, the Cluster object will stillbe kept in the database with anError status. If any validations failsduring scaling theActive Cluster, it will be kept with anActivestatus. In both cases status description will contain error messages about thereasons of failure.

2. InfraUpdating¶

This status means that the Provisioning plugin is performing someinfrastructure updates.

3. Spawning¶

Sahara sends requests to OpenStack for all resources to be created:

• VMs
• Volumes
• Floating IPs (if Sahara is configured to use Floating IPs)

It takes some time for OpenStack to schedule all the required VMs and Volumes,so sahara will wait until all of the VMs are in anActive state.

4. Waiting¶

Sahara waits while VMs’ operating systems boot up and all internalinfrastructure components like networks and volumes are attached and ready touse.

5. Preparing¶

Sahara prepares a Cluster for starting. This step includes generating the/etc/hosts file or changing/etc/resolv.conf file (if you use Designateservice), so that all instances can access each other by a hostname.Also Sahara updates theauthorized_keys file on each VM, so that VMs cancommunicate without passwords.

6. Configuring¶

Sahara pushes service configurations to VMs. Both XML and JSON basedconfigurations and environmental variables are set on this step.

7. Starting¶

Sahara is starting Hadoop services on Cluster’s VMs.

8. Active¶

Active status means that a Cluster has started successfully and is ready to runEDP Jobs.

1. Validating¶

Sahara checks the scale/shrink request for validity. The Plugin method calledfor performing Plugin specific checks is different from the validation methodin creation.

2. Scaling¶

Sahara performs database operations updating all affected existing Node Groupsand creating new ones to join the existing Node Groups.

3. Adding Instances¶

Status is similar toSpawning in Cluster creation. Sahara adds requiredamount of VMs to the existing Node Groups and creates new Node Groups.

4. Configuring¶

Status is similar toConfiguring in Cluster creation. New instances arebeing configured in the same manner as already existing ones. The VMs in theexisting Cluster are also updated with a new/etc/hosts file or/etc/resolv.conf file.

5. Decommissioning¶

Sahara stops Hadoop services on VMs that will be deleted from a Cluster.Decommissioning a Data Node may take some time because Hadoop rearranges datareplicas around the Cluster, so that no data will be lost after that Data Nodeis deleted.

6. Deleting Instances¶

Sahara sends requests to OpenStack to release unneeded resources:

• VMs
• Volumes
• Floating IPs (if they are used)

7. Active¶

The sameActive status as after Cluster creation.

1. Deleting¶

The only step, that releases all Cluster’s resources and removes it from thedatabase.