s2i-example-migration

An example repository of a project to show how to migrate an already existing OpenShift Python s2i application to Thoth (demo).

See https://thoth-station.ninja for more info on Thoth.

Usage

The application is created out of this repository. It follows OpenShift Python s2i build process. The built application is a simple TensorFlow application that prints "Hello, Thoth!" to the console using TensorFlow.

Mind the app.py and requirements.txt files needed for the application present in the Git repository. The openshift.yaml file is a manifest used to deploy this application to an OpenShift cluster.

Installation

Log in to an OpenShift cluster and select namespace you would like to use:

oc login
oc project thoth-s2i-demo

To install this application to an OpenShift cluster run the following command:

oc create -f https://raw.githubusercontent.com/thoth-station/s2i-example-migration/master/openshift.yaml

Migrating to Thoth

To migrate this application to Thoth, use a tool called thoth-s2i:

pip install thoth-s2i

Note

The oc binary needs to be installed on your system and you need to be logged in into an OpenShift cluster in order to follow the upcomming steps.

First, let's have a look at the namespace - what build configs are present and ready to be migrated:

thoth-s2i report --namespace thoth-s2i-demo
2020-04-29 16:04:48,903 [218204] INFO     thoth.s2i.objs: Loading file content from '/tmp/tmp5x6eiurw'
2020-04-29 16:04:48,917 [218204] INFO     thoth.s2i.objs: Found 's2i-example-tensorflow' of kind 'buildconfig' in '/tmp/tmp5x6eiurw'
2020-04-29 16:04:50,041 [218204] INFO     thoth.s2i.objs: Loading file content from '/tmp/tmp5x6eiurw'
2020-04-29 16:04:50,069 [218204] INFO     thoth.s2i.objs: Found 'python-36' of kind 'imagestream' in '/tmp/tmp5x6eiurw'
2020-04-29 16:04:50,069 [218204] INFO     thoth.s2i.objs: Found 's2i-example-tensorflow' of kind 'imagestream' in '/tmp/tmp5x6eiurw'
2020-04-29 16:04:50,070 [218204] INFO     thoth.s2i.objs: Found 's2i-thoth-ubi8-py36' of kind 'imagestream' in '/tmp/tmp5x6eiurw'
📝 s2i-example-tensorflow
      🠒 strategy: 'Source'
      🠒 image_stream: 'python-36'
      🠒 image_stream_tag: 'latest'
      🠒 is_s2i: True
      🠒 s2i_image_name: 'registry.access.redhat.com/ubi8/python-36'
      🠒 s2i_image_tag: 'latest'

The report printed aggregates information about the namespace in a human readable form (see options available to adjust output based on label selector or to create JSON/YAML output).

Now, let's check what Thoth s2i container images are available:

thoth-s2i images
✔ quay.io/thoth-station/s2i-thoth-ubi8-py36
✔ quay.io/thoth-station/s2i-thoth-f31-py37

Next, let's issue a dry run migration so we know what changes the tool will make to the cluster. We choose s2i-thoth-ubi-py36 as a Python s2i drop-in replacement of the UBI 8 Python 3.6 container image we are already using in the deployment:

THAMOS_REQUIREMENTS_FORMAT=pip thoth-s2i migrate -n thoth-s2i-demo --dry-run --insert-env-vars --s2i-thoth quay.io/thoth-station/s2i-thoth-ubi8-py36
2020-04-29 16:21:44,455 [220851] INFO     thoth.s2i.objs: Loading file content from '/tmp/tmp5hmcksot'
2020-04-29 16:21:44,481 [220851] INFO     thoth.s2i.objs: Found 's2i-example-tensorflow' of kind 'buildconfig' in '/tmp/tmp5hmcksot'
2020-04-29 16:21:44,481 [220851] INFO     thoth.s2i.lib: Patching BuildConfig 's2i-example-tensorflow', replacing 'python-36:latest' with 's2i-thoth-ubi8-py36:latest'
2020-04-29 16:21:44,481 [220851] INFO     thoth.s2i.objs: Inserting Thoth and Thamos specific environment variables to 's2i-example-tensorflow'
2020-04-29 16:21:44,482 [220851] WARNING  thoth.s2i: Dry run will not import image into OpenShift's registry
--
apiVersion: build.openshift.io/v1
kind: BuildConfig
metadata:
  creationTimestamp: '2020-04-29T14:03:57Z'
  labels:
    app: s2i-example-tensorflow
  name: s2i-example-tensorflow
  namespace: thoth-s2i-demo
  resourceVersion: '4545199'
  selfLink: /apis/build.openshift.io/v1/namespaces/thoth-s2i-demo/buildconfigs/s2i-example-tensorflow
  uid: 72224227-fd18-49e9-aa91-2661cb1da325
spec:
  failedBuildsHistoryLimit: 2
  nodeSelector: null
  output:
    to:
      kind: ImageStreamTag
      name: s2i-example-tensorflow:latest
  postCommit: {}
  resources:
    limits:
      cpu: '1'
      memory: 1Gi
    requests:
      cpu: '1'
      memory: 1Gi
  runPolicy: Serial
  source:
    git:
      ref: master
      uri: https://github.com/thoth-station/s2i-example-migration
    type: Git
  strategy:
    sourceStrategy:
      env:
      - name: ENABLE_PIPENV
        value: '1'
      - name: UPGRADE_PIP_TO_LATEST
        value: ''
      - name: THOTH_DRY_RUN
        value: '0'
      - name: THOTH_ADVISE
        value: '1'
      - name: THOTH_ASSEMBLE_DEBUG
        value: '1'
      - name: THOTH_FROM_MASTER
        value: '0'
      - name: THOTH_ERROR_FALLBACK
        value: '1'
      - name: THAMOS_VERBOSE
        value: '0'
      - name: THAMOS_FORCE
        value: '0'
      - name: THAMOS_DEBUG
        value: '0'
      - name: THAMOS_CONFIG_EXPAND_ENV
        value: '0'
      - name: THAMOS_REQUIREMENTS_FORMAT
        value: 'pip'
      - name: THAMOS_NO_PROGRESSBAR
        value: '1'
      - name: THAMOS_NO_INTERACTIVE
        value: '1'
      - name: THAMOS_DEV
        value: '0'
      - name: THAMOS_REQUIREMENTS_FORMAT
        value: 'pip'
      from:
        kind: ImageStreamTag
        name: s2i-thoth-ubi8-py36:latest
    type: Source
  successfulBuildsHistoryLimit: 1
  triggers:
  - imageChange:
      lastTriggeredImageID: registry.access.redhat.com/ubi8/python-36@sha256:7c29ae7f78f2f899b743455fdc6e8068c0ac18a27fdae58ce3123acdc116b087
    type: ImageChange
status:
  lastVersion: 1

Based on the output, we see changes in the builder image - now we use ImageStreamTag named s2i-thoth-ubi8-py36:latest. We also see Thoth specific configuration options present in the environment variables of the build config. To understand their semantics, refer to s2i-thoth documentation and Thamos.

The environment variable called THAMOS_REQUIREMENTS_FORMAT specifies a requirements.txt file will be searched during the build (instead of using default Pipfile/Pipfile.lock files as produced by Pipenv).

After the changes done have been reviewed, we can submit them to the cluster by removing the --dry-run option:

THAMOS_REQUIREMENTS_FORMAT=pip thoth-s2i migrate -n thoth-s2i-demo --insert-env-vars --s2i-thoth quay.io/thoth-station/s2i-thoth-ubi8-py36 --import-image --trigger-build
2020-04-29 16:26:27,857 [221257] INFO     thoth.s2i.objs: Loading file content from '/tmp/tmpu46k0k9n'
2020-04-29 16:26:27,885 [221257] INFO     thoth.s2i.objs: Found 's2i-example-tensorflow' of kind 'buildconfig' in '/tmp/tmpu46k0k9n'
2020-04-29 16:26:27,885 [221257] INFO     thoth.s2i.lib: Patching BuildConfig 's2i-example-tensorflow', replacing 'python-36:latest' with 's2i-thoth-ubi8-py36:latest'
2020-04-29 16:26:27,885 [221257] INFO     thoth.s2i.objs: Inserting Thoth and Thamos specific environment variables to 's2i-example-tensorflow'
2020-04-29 16:26:27,886 [221257] INFO     thoth.s2i.objs: Applying changes made to 's2i-example-tensorflow' to the cluster
2020-04-29 16:26:32,727 [221257] INFO     thoth.s2i.objs: Triggering build for 's2i-example-tensorflow' in namespace 'thoth-s2i-demo'
imagestream.image.openshift.io/s2i-thoth-ubi8-py36 imported

Name:                 s2i-thoth-ubi8-py36
Namespace:            thoth-s2i-demo
Created:              2 hours ago
Labels:                       app=s2i-example-tensorflow
Annotations:          kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"image.openshift.io/v1","kind":"ImageStream","metadata":{"annotations":{},"labels":{"app":"s2i-example-tensorflow"},"name":"s2i-thoth-ubi8-py36","namespace":"thoth-s2i-demo"},"spec":{"tags":[{"from":{"kind":"DockerImage","name":"quay.io/thoth-station/s2i-thoth-ubi8-py36"},"name":"latest","referencePolicy":{"type":"Source"}}]}}

                      openshift.io/image.dockerRepositoryCheck=2020-04-29T12:52:23Z
Docker Pull Spec:     image-registry.openshift-image-registry.svc:5000/thoth-s2i-demo/s2i-thoth-ubi8-py36
Image Lookup:         local=false
Unique Images:                1
Tags:                 1

latest
  tagged from quay.io/thoth-station/s2i-thoth-ubi8-py36

  * quay.io/thoth-station/s2i-thoth-ubi8-py36@sha256:1d7d42821cfdb30d9ca5f8da488741c02f87a75ffe9ef32d2bccb2f5a0005321
      2 hours ago

Image Name:   s2i-thoth-ubi8-py36:latest
Docker Image: quay.io/thoth-station/s2i-thoth-ubi8-py36@sha256:1d7d42821cfdb30d9ca5f8da488741c02f87a75ffe9ef32d2bccb2f5a0005321
Name:         sha256:1d7d42821cfdb30d9ca5f8da488741c02f87a75ffe9ef32d2bccb2f5a0005321
Created:      22 seconds ago
Annotations:  image.openshift.io/dockerLayersOrder=ascending
Image Size:   289.8MB in 7 layers
Layers:               74.02MB sha256:78afc5364ad2c981e4a4919f535aaefef9ac2f990837be01c766764e025b1f31
              1.564kB sha256:58e1deb9693dfb1704ccce2f1cf0e4d663ac77098a7a0f699708a71549cbd924
              16.67MB sha256:1d3caaab0e6b8f6421152e3e992b9af724fb775da1fbc232ce24b02d5a910efd
              124.6MB sha256:a4de40bef32d2d442436fd227ae0ff8950dff0bb8f2861e8d6550ed5d54d0b11
              55.32MB sha256:7e39dc43e16c66fcceffdded184903e157be1091e8829983007b3c946c094c76
              702B    sha256:333a0e4d4b1fa5f0d37144430383144f26b1f9f86884b254658f353c829400be
              19.22MB sha256:dd89c8518b4768ce3f9fd29940f0e0548609a371d416ddf5622864d9bd5ea872
Image Created:        6 hours ago
Author:               <none>
Arch:         amd64
Entrypoint:   container-entrypoint
Command:      /bin/sh -c $STI_SCRIPTS_PATH/usage
Working Dir:  /opt/app-root/src
User:         1001
Exposes Ports:        8080/tcp
Docker Labels:        architecture=x86_64
              build-date=2020-04-23T10:39:48.254767
              com.redhat.build-host=cpt-1001.osbs.prod.upshift.rdu2.redhat.com
              com.redhat.component=python-36-container
              com.redhat.license_terms=https://www.redhat.com/en/about/red-hat-end-user-license-agreements#UBI
              description=Thoth's Source-to-Image for Python 3.6 applications. This toolchain is based on Red Hat UBI8. It includes pipenv.
              distribution-scope=public
              io.k8s.description=Thoth's Source-to-Image for Python 3.6 applications. This toolchain is based on Red Hat UBI8. It includes pipenv.
              io.k8s.display-name=Thoth Python 3.6-ubi8 S2I
              io.openshift.expose-services=8080:http
              io.openshift.s2i.scripts-url=image:///usr/libexec/s2i
              io.openshift.tags=python,python36
              io.s2i.scripts-url=image:///usr/libexec/s2i
              maintainer=Thoth Station <aicoe-thoth@redhat.com>
              name=thoth-station/s2i-thoth-ubi8-py36:v0.12.0
              ninja.thoth-station.version=0.6.0-dev
              release=0
              summary=Thoth's Source-to-Image for Python 3.6 applications
              url=https://access.redhat.com/containers/#/registry.access.redhat.com/ubi8/python-36/images/1-89
              usage=s2i build https://github.com/sclorg/s2i-python-container.git --context-dir=3.6/test/setup-test-app/ ubi8/python-36 python-sample-app
              vcs-ref=cc087e1dcb33f4838e0a939b20a384149a70bc99
              vcs-type=git
              vendor=AICoE at the Office of the CTO, Red Hat Inc.
              version=0.12.0
Environment:  PATH=/opt/app-root/src/.local/bin/:/opt/app-root/src/bin:/opt/app-root/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
              container=oci
              SUMMARY=Thoth's Source-to-Image for Python 3.6 applications
              DESCRIPTION=Thoth's Source-to-Image for Python 3.6 applications. This toolchain is based on Red Hat UBI8. It includes pipenv.
              STI_SCRIPTS_URL=image:///usr/libexec/s2i
              STI_SCRIPTS_PATH=/usr/libexec/s2i
              APP_ROOT=/opt/app-root
              HOME=/opt/app-root/src
              PLATFORM=el8
              NODEJS_VER=10
              PYTHON_VERSION=3.6
              PYTHONUNBUFFERED=1
              PYTHONIOENCODING=UTF-8
              LC_ALL=en_US.UTF-8
              LANG=en_US.UTF-8
              PIP_NO_CACHE_DIR=off
              BASH_ENV=/opt/app-root/etc/scl_enable
              ENV=/opt/app-root/etc/scl_enable
              PROMPT_COMMAND=. /opt/app-root/etc/scl_enable
              THOTH_S2I_VERSION=v0.12.0
              THAMOS_NO_PROGRESSBAR=1
              THAMOS_NO_EMOJI=1

We also added --import-image option so that s2i-thoth-ubi-8-py36 is imported to the namespace and available via OpenShift's image stream. The --trigger-build option makes sure all the builds are triggered on this change even if the BuildConfig has no configuration change build trigger set up.

To double check changes, we can ask for the cluster report again:

thoth-s2i report -n thoth-s2i-demo
2020-04-29 16:27:43,860 [221475] INFO     thoth.s2i.objs: Loading file content from '/tmp/tmpvx34u93m'
2020-04-29 16:27:43,885 [221475] INFO     thoth.s2i.objs: Found 's2i-example-tensorflow' of kind 'buildconfig' in '/tmp/tmpvx34u93m'
2020-04-29 16:27:44,936 [221475] INFO     thoth.s2i.objs: Loading file content from '/tmp/tmpvx34u93m'
2020-04-29 16:27:44,979 [221475] INFO     thoth.s2i.objs: Found 'python-36' of kind 'imagestream' in '/tmp/tmpvx34u93m'
2020-04-29 16:27:44,979 [221475] INFO     thoth.s2i.objs: Found 's2i-example-tensorflow' of kind 'imagestream' in '/tmp/tmpvx34u93m'
2020-04-29 16:27:44,980 [221475] INFO     thoth.s2i.objs: Found 's2i-thoth-ubi8-py36' of kind 'imagestream' in '/tmp/tmpvx34u93m'
📝 s2i-example-tensorflow
              🠒 strategy: 'Source'
              🠒 image_stream: 's2i-thoth-ubi8-py36'
              🠒 image_stream_tag: 'latest'
              🠒 is_s2i: True
              🠒 is_s2i_thoth: True
              🠒 s2i_image_name: 'quay.io/thoth-station/s2i-thoth-ubi8-py36'
              🠒 s2i_image_tag: 'latest'

Clean up

To remove this application from the namespace:

oc delete -f https://raw.githubusercontent.com/thoth-station/s2i-example-migration/master/openshift.yaml
# Or, alternatively:
#   oc delete bc,dc,is -l app=s2i-example-tensorflow