telephoneorg/etcd repository overview

⁠etcd (auto-configuring) for Kubernetes

⁠Maintainer

Joe Black | [email protected]⁠ | github⁠

⁠Description

Minimal image, favoring conventions over configuration, that is 99% auto-configuring. Designed to be used as a static pod in a kubernetes manifest but surely there could be other pragmatic uses. This image is based on a custom, minimal version of Debian Linux for Container OS's.

⁠Build Environment

Build environment variables are often used in the build script to bump version numbers and set other options during the docker build phase. Their values can be overridden using a build argument of the same name.

• ETCD_VERSION

The following variables are standard in most of our dockerfiles to reduce duplication and make scripts reusable among different projects:

• APP: etcd
• USER: etcd
• HOME /var/lib/etcd

⁠Run Environment

Run environment variables are used in the entrypoint script to render configuration templates, perform flow control, etc. These values can be overridden when inheriting from the base dockerfile, specified during docker run, or in kubernetes manifests in the env array.

• ETCD_BOOTSTRAP_NAMES: Comma seperated list of names. Iterated and resolved as such: $name.$(dnsdomainname) to build the value for ETCD_INITIAL_CLUSTER.
• ETCD_INITIAL_CLUSTER_TOKEN: Passed through to etcd. If not set, static, insecure default is used.

Documentation refs:

• https://coreos.com/etcd/docs/latest/faq.html⁠
• https://coreos.com/etcd/docs/latest/op-guide/configuration.html⁠
• https://coreos.com/etcd/docs/latest/op-guide/maintenance.html⁠
• https://coreos.com/etcd/docs/latest/op-guide/recovery.html⁠

⁠Usage

⁠Under docker (pre-built)

All of our docker-* repos in github have CI pipelines that push to docker cloud/hub.

This image is available at:

• https://hub.docker.com/r/telephoneorg/etcd⁠
• https://store.docker.com/community/images/telephoneorg/etcd⁠
• docker pull telephoneorg/etcd

To run:

docker run -d \
    --name rabbitmq \
    -h host1.domain.local \
    -e "ETCD_BOOTSTRAP_NAMES=host1,host2" \
    telephoneorg/rabbitmq

NOTE: Please reference the Run Environment section for a list of available environment variables.

⁠Under docker-compose

Pull the images

docker-compose pull

Start application and dependencies

# start in foreground
docker-compose up --abort-on-container-exit

# start in background
docker-compose up -d

⁠Under Kubernetes

• Edit the manifests under kubernetes/<environment> to reflect your specific environment and configuration.
• Deploy etcd as static pod:

scp kubernetes/production/static.yaml $node:/etc/kubernetes/manifests/etcd-static.yaml

⁠Troubleshooting

⁠Problem

etcd server on one node is down and refuses to connect back to the cluster.

⁠Solutions

• Check that the ip addresses haven't changed