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• release-4.4
• release-4.3

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I do not have access to the redhat repo for downloading the images. So I changed the images with other simple ones, the issue is the leader-elector container is not able to pick up the name.

Will not report event: 'Normal' '%v became leader' '$(hostname)'
I0524 08:53:43.227183 1 leaderelection.go:215] sucessfully acquired lease default/example
$(hostname) is the leader
$(hostname) is the leader

Below is the docker file:

FROM golang:1.13 as builder

ADD election /go/src/k8s.io/contrib/election
RUN cd /go/src/k8s.io/contrib/election
&& CGO_ENABLED=0 GOOS=linux GO111MODULE=off go build -a -installsuffix cgo -ldflags '-w' -o leader-elector example/main.go

FROM debian:jessie

ENV DEBIAN_FRONTEND=noninteractive

RUN
apt-get update &&
apt-get install -y ca-certificates &&
rm -rf /var/lib/apt/lists/*

COPY --from=builder /go/src/k8s.io/contrib/election/leader-elector /usr/bin/

USER 1001

ENTRYPOINT [ "leader-elector", "--id=$(hostname)" ]

LABEL
io.k8s.description="This is a component of OpenShift Container Platform and provides a leader-elector sidecar container."
com.redhat.component="leader-elector-container"
maintainer="Michal Dulko [email protected]"
name="openshift/ose-leader-elector"
summary="This image provides leader election functionality and can be used as a sidecar container."
io.k8s.display-name="leader-elector"
version="v4.0.0"
io.openshift.tags="openshift"

The following branches are being fast-forwarded from the current development branch (master) as placeholders for future releases. No merging is allowed into these release branches until they are unfrozen for production release.

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• release-4.3
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Description

We are implementing a leader election strategy for a High Availability service. We are using the ose-leader-elector-rhel8:v4.7 as the base image for the sidecar container, here you have the hole implementation:

-   name: jupyterhub-ha-sidecar
    image: 'registry.redhat.io/openshift4/ose-leader-elector-rhel8:v4.7'
    args:
      - '--election=jupyterhub-ha-election'
      - '--election-namespace=$(NAMESPACE)'
      - '--http=0.0.0.0:4040'
      - '--id=$(POD_NAME)'
    env:
      - name: NAMESPACE
        valueFrom:
          fieldRef:
            apiVersion: v1
            fieldPath: metadata.namespace
      - name: POD_NAME
        valueFrom:
          fieldRef:
            apiVersion: v1
            fieldPath: metadata.name

The current implementation works great, but given a certain amount of time we bump into the following error in every pod that's running the sidecar container:

E0907 03:43:50.043988       1 leaderelection.go:253] error retrieving endpoint: Get "https://172.30.0.1:443/api/v1/namespaces/redhat-ods-applications/endpoints/jupyterhub-ha-election": http2: no cached connection was available

With this issue, the leader election strategy doesn't work, as the sidecar images don't provide the current name of the leader. Restarting the container fixes the problem.

Looks like the entrypoint doesn't substitute the command here:

ENTRYPOINT [ "leader-elector", "--id=$(hostname)" ]

As explained in https://docs.docker.com/engine/reference/builder/#exec-form-entrypoint-example, the normal shell processing doesn't happen, leaving literal $(hostname) to the leader-elector arguments.

One way to fix it could be calling a script like the run.sh.

The following branches are being fast-forwarded from the current development branch (master) as placeholders for future releases. No merging is allowed into these release branches until they are unfrozen for production release.

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• release-4.2

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