SAS recommends updating the SAS Viya platform at least every 4 months on stable cadence or every 6 months on Long-term Support (LTS) cadence. The SAS Viya platform administrator must understand the SAS Viya platform deployment update process, most specifically regarding the CAS servers. CAS servers will be updated only when their associated CASDeployment custom resources are updated and the CAS server restarted to use the new CASDeployment custom resources version.
In this post, I will share with you key considerations you must know to successfully update CAS servers in your SAS Viya platform deployments.
When the SAS Viya platform administrator needs to update the SAS Viya platform deployment, the SAS® Viya® Platform Administration guide suggests the following process.
create-cas-server.sh
script.
This process is well described but as a SAS Viya platform administrator, I would like to provide you with more detailed processes regarding steps 4 and 6, including when you need to restart CAS servers and some of the CAS server features that affect your restart decisions.
The manifests that define CAS servers are provided by SAS with each SAS Viya platform deployment assets in the /sas-bases/overlays/cas-server/
directory. These manifests are potentially updated with each SAS Viya platform update. Normally, the manifests in that directory are only used by the default CAS server.
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If additional CAS servers were added to the SAS Viya platform deployment, they were created by the SAS Viya platform administrator using the create-cas-server.sh
script. This script copies the SAS provided set of CAS server manifests to a new directory, typically in /site-config
, to create the new CAS server.
When the SAS Viya platform deployment is updated, the SAS Viya platform deployment assets are replaced. All SAS Viya platform deployment customizations, typically in /site-config
, are not updated.
Because the default CAS server directly uses the manifests provided with the new assets in the /sas-bases/overlays/cas-server/
directory:
Regarding additional CAS servers, each CASDeployment custom resource was generated from its own set of manifests that were copied from /sas-bases/overlays/cas-server/
directory by the create-cas-server.sh
script. These additional CAS server manifests are not updated automatically when the SAS Viya platform deployment assets are updated. To update the additional CAS servers:
create-cas-server.sh
script from the updated SAS Viya platform deployment assets. This updates each additional CAS server CASDeployment custom resource.
How a CAS server is restarted depends on how CAS is configured and how the deployment is managed. See SAS Viya – CAS Server Life Cycle Management for details on stopping and restarting CAS servers.
At least, the CAS server can be restarted using Kubernetes commands. The SAS Viya platform administrator just must delete the existing CAS pods that will restart automatically using the latest CASDeployment custom resources. Using this restart method, all CAS tables must be reloaded, and all CAS sessions are lost.
If the SAS Viya platform was deployed using the Deployment Operator or the sas-orchestration command, the following features can be enabled by the SAS Viya platform administrator and affect the CAS server restart options.
Note: It is not possible to enable CAS auto-restart and state transfer in the same SAS Viya platform deployment.xxx
sas-config
directory. This file is named cas-auto-restart.yaml
and is located in the sas-bases/examples/cas/configure/
directory.sas-config/cas-auto-restart.yaml
manifest must be referenced into the transformer
field of the kustomization.yaml
file.
kustomization.yaml
file:sas-bases/overlays/cas-server/state-transfer
manifests into the resources
field.sas-bases/overlays/cas-server/state-transfer/support-state-transfer.yaml
manifests into the transformer
field.create-cas-server.sh
script and its -r
or --transfer
option to enable the CAS server state transfer.resources
field of the kustomization.yaml
file.
In the table below, I tried to summarize all the steps you must pass through to update your SAS Viya platform deployment depending on the SAS Viya platform deployment methods you used, and the restart features you enable for your CAS servers.
This table will help you define the SAS Viya platform update process that you must use in your specific environment.
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Download the new SAS Viya platform deployment assets. | |||||||||||||||||
Review the SAS Viya platform deployment notes. | |||||||||||||||||
If you have multiple CAS servers in the SAS Viya deployment, regenerate their set of manifests using the create-cas-server.sh script. |
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Inform the SAS Viya platform users and administrators about the upcoming software update. | |||||||||||||||||
Re-deploy SAS Viya platform
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Restart all CAS servers after the SAS Viya platform deployment is updated.
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I hope this article has been helpful to you.
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