Deploy and Scale Swift in the Overcloud

This guide assumes that you are ready to deploy a new overcloud. To ensure that Swift nodes are all using the same Ring, some manual steps are required.

Initial Deploy

To correctly deploy Swift, we need to manually manage the Swift Rings. This can be achieved by disabling the Ring building process in TripleO by setting the SwiftRingBuild and RingBuild parameters both to false. For example:

  SwiftRingBuild: false
  RingBuild: false


If this is saved in a file named deploy-parameters.yaml then it can be deployed with openstack overcloud deploy --templates -e deploy-parameters.yaml.

After the deploy is completed, you will need to ssh onto the overcloud node as the heat-admin user and switch to the root user with sudo -i. The IP addresses is available in the output of openstack server list. Once connected, in the /etc/swift/ directory follow the instructions in the Swift documentation to create the Rings.

After this is completed you will need to copy the /etc/swift/*.ring.gz and /etc/swift/*.builder files from the controller to all other controllers and Swift storage nodes. These files will also be used when adding additional Swift nodes. You should have six files:



These files will be updated each time a new node is added with swift-ring-builder.

Scaling Swift

TripleO doesn’t currently automatically update and scale Swift Rings. This needs to be done manually, with similar steps to the above initial deployment. First we need to define how many dedicated Swift nodes we want to deploy with the ObjectStorageCount parameter. In this example we are adding two Swift nodes:

  SwiftRingBuild: false
  RingBuild: false
  ObjectStorageCount: 2

After we have deployed again with this new environment we will have two Swift nodes that need to be added to the ring we created during the initial deployment. Follow the instructions on Managing the Rings to add the new devices to the rings and copy the new rings to all nodes in the Swift cluster.


Also read the section on Scripting ring creation to automate this process of scaling the Swift cluster.

Viewing the Ring

The swift ring can be viewed on each node with the swift-ring-builder command. It can be executed against all of the *.builder files. Its output will display all the nodes in the Ring like this:

$ swift-ring-builder /etc/swift/object.builder
/etc/swift/object.builder, build version 4
1024 partitions, 3.000000 replicas, 1 regions, 1 zones, 3 devices, 0.00 balance, 0.00 dispersion
The minimum number of hours before a partition can be reassigned is 1
The overload factor is 0.00% (0.000000)
Devices:    id  region  zone      ip address  port  replication ip  replication port      name weight partitions balance meta
             0       1     1  6000              6000        d1 100.00       1024    0.00
             1       1     1  6000              6000        d1 100.00       1024    0.00
             2       1     1  6000              6000        d1 100.00       1024    0.00

Ring configuration be verified by checking the hash of the *.ring.gz files. It should be the same on all nodes in the ring.:

$ sha1sum /etc/swift/*.ring.gz
d41c1b4f93a98a693a6ede074a1b78585af2dc89  /etc/swift/account.ring.gz
1d10d8cb826308a058c7089fdedfeca122426da9  /etc/swift/container.ring.gz
f26639938660ee0111e4e7bc1b45f28a0b9f6079  /etc/swift/object.ring.gz

You can also check this by using the swift-recon command on one of the overcloud nodes. It will query all other servers and compare all checksums and a summary like this:

[root@overcloud-controller-0 ~]# swift-recon --md5
--> Starting reconnaissance on 3 hosts (object)
[2016-10-14 12:37:11] Checking ring md5sums
3/3 hosts matched, 0 error[s] while checking hosts.
[2016-10-14 12:37:11] Checking swift.conf md5sum
3/3 hosts matched, 0 error[s] while checking hosts.