Cloud Pak for Business Automation

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  • 1.  Planning installation

    Posted Mon May 24, 2021 11:25 AM

    Hi, documentation says that you need a minimum of 3 Master and 8 Worker nodes to install all CP4A capabilities.

    We want to make a stable installation of only some components (Operator, Automation Decision Services, BAI, BAW, ODM and UMS). Provided that HA is not a requirement, and we don't care about the consensus, do you think it can work on 1 Master and 3 Workers? or is there a limitation to make it work with only 1 Master?



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    Eduardo Izquierdo Lázaro
    Automation Architect
    DECIDE
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  • 2.  RE: Planning installation

    Posted Tue May 25, 2021 03:15 AM
    Hello Eduardo,

    I assume you are deploying on OCP. In this case, 1 master node is not a configuration supported by RedHat. You need at least 3 master nodes. For the worker nodes, it will depend on what you deploy and the number of cores of each nodes. 

    Cheers,
    Fadi

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    Fadi Sandakly
    Decision Management SME - Cloud Pak for Automation
    IBM EMEA
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    Original Message


  • 3.  RE: Planning installation

    Posted Tue May 25, 2021 04:10 AM
    Hi Fadi, yes I was talking about OCP. Uf, that are strong requirements.
    Best regards.

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    Eduardo Izquierdo Lázaro
    Automation Architect
    DECIDE
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    Original Message


  • 4.  RE: Planning installation

    Posted Tue May 25, 2021 07:10 AM
    if master goes down, there cannot be any new pods scheduled to worker nodes and also if a pod comes down, it will not come back up due to controller manager and schedulers being down on master. In general k8s environments, the workload can still run on worker nodes, but with risks involved. Also etcd needs a minimum to 3 instances for safe consensus, else it may be hard to recover the entire cluster if you need it. You need to weigh the risks involved vs costs.

    Vishy

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    Vishy Kasinadhuni
    Travelers
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    Original Message


  • 5.  RE: Planning installation

    Posted Tue May 25, 2021 03:03 PM
    Hello Eduardo,
    the 3 masters are mandatory. In the documentation the size of a worker is 8 cores and 32 Gb of RAM, so the minimum is 64 cores.
    That could be minimized by reducing the replication.
    You should take a look to the over-commit OCP feature which is a way to install applications which over-commit the limits of the workers. see https://docs.openshift.com/container-platform/4.7/nodes/clusters/nodes-cluster-overcommit.html

    We are installing ADS/BAI/ODM (HA available) no BAW on several configurations, the smallest one is composed of 3 masters and 5 workers, this cluster is over committed.
    This set of workers contains 32 cores (64 cpu) and 256 Gb of RAM.

    Best regards,
    Pierre-André Paumelle



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    Pierre-Andre Paumelle
    Performance Architect
    IBM
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    Original Message