Uploaded image for project: 'Container Tools'
  1. Container Tools
  2. RUN-1558

Make image pulls more resilient

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    • openshift-4.13
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      OCP/Telco Definition of Done
      Epic Template descriptions and documentation.

      <--- Cut-n-Paste the entire contents of this description into your new Epic --->

      Epic Goal

      • When the network is unstable, crio is unable to pull images from docker.io while docker cli can. It makes OCP4 less tolerant to network outage than OCP3

      Docker cli has a retry mechanism per blob which is very efficient which is not the case with crio stack. 

      Why is this important?

      • For customers planning to migrate from OCP 3.11 to 4.x, this issue could make them worried about the cluster/applications availability when the network becomes unstable or the company proxy drops a connection.

      Scenarios

      • Pull with buildah --> KO
      1. https_proxy=<obfuscated> buildah pull docker://docker.io/image:tag
        Getting image source signatures
        Copying blob 04f220ee9266 done
        Copying blob 034655750c88 done
        Copying blob f0b757a2a0f0 done
        Copying blob 89c8a77f7842 done
        Copying blob 4bbcce26bc5e done
        Copying blob 7b1a6ab2e44d done
        Copying blob d1de5652303b done
        Copying blob ef669123e59e done
        Copying blob b14b1ba1d651 done
        Copying blob e5cec468d3a6 done
        while pulling "docker://docker.io/image:tag" as "docker.io/image:tag": Error writing blob: error storing blob to file "/var/tmp/storage487953815/6": read tcp x.x.x.x:port->x.x.x.x:3128: read: connection reset by peer
      • Pull with docker --> OK
      1. https_proxy=<obfuscated> docker pull docker.io/image:tag
        Trying to pull repository docker.io/library/image ...
        10.6.5: Pulling from docker.io/library/image
        7b1a6ab2e44d: Pull complete
        034655750c88: Pull complete
        f0b757a2a0f0: Pull complete
        4bbcce26bc5e: Pull complete
        04f220ee9266: Pull complete
        89c8a77f7842: Pull complete
        d1de5652303b: Pull complete
        ef669123e59e: Pull complete
        e5cec468d3a6: Pull complete
        b14b1ba1d651: Pull complete
        Status: Downloaded newer image for docker.io/image:tag

      Docker logs show that it has to retry a blob when pulling the image

      1. journalctl -u docker | grep resume
        dockerd-current[pid]: time="" level=debug msg="attempting to resume download of \"sha256:7b1a6ab2e44d...\" from 653653 bytes"

      Acceptance Criteria

      • CI - MUST be running successfully with tests automated
      • Release Technical Enablement - Provide necessary release enablement details and documents.
      • ...

      Dependencies (internal and external)

      1. ...

      Previous Work (Optional):

      Open questions::

      Done Checklist

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              rhn-engineering-mitr Miloslav Trmač
              umohnani Urvashi Mohnani
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                Created:
                Updated:
                Resolved: