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fixing README

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ricardop 2018-06-29 01:45:16 +02:00
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README.md
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@ -7,34 +7,17 @@ A caching proxy for Docker; allows centralized management of registries and thei
### What?
Created as an evolution and simplification of [docker-caching-proxy-multiple-private](https://github.com/rpardini/docker-caching-proxy-multiple-private)
using the `HTTPS_PROXY` mechanism and injected CA root certificates instead of `/etc/hosts` hacks and _`--insecure-registry`
using the `HTTPS_PROXY` mechanism and injected CA root certificates instead of `/etc/hosts` hacks and `--insecure-registry`
As a bonus it allows for centralized management of Docker registry credentials.
Main feature is Docker layer/image caching, even from S3, Google Storage, etc. As a bonus it allows for centralized management of Docker registry credentials.
You configure the Docker clients (_err... Kubernetes Nodes?_) once, and then all configuration is done on the proxy --
for this to work it requires inserting a root CA certificate into system trusted root certs.
#### Why not use Docker's own registry, which has a mirror feature?
Yes, Docker offers [Registry as a pull through cache](https://docs.docker.com/registry/recipes/mirror/), *unfortunately*
it only covers the DockerHub case. It won't cache images from `quay.io`, `k8s.gcr.io`, `gcr.io`, or any such, including any private registries.
That means that your shiny new Kubernetes cluster is now a bandwidth hog, since every image will be pulled from the
Internet on every Node it runs on, with no reuse.
This is due to the way the Docker "client" implements `--registry-mirror`, it only ever contacts mirrors for images
with no repository reference (eg, from DockerHub).
When a repository is specified `dockerd` goes directly there, via HTTPS (and also via HTTP if included in a
`--insecure-registry` list), thus completely ignoring the configured mirror.
#### Docker itself should provide this.
Yeah. Docker Inc should do it. So should NPM, Inc. Wonder why they don't. 😼
### Usage
- Run the proxy on a dedicated machine.
- Expose port 3128
- Run the proxy on a host close to the Docker clients
- Expose port 3128 to the network
- Map volume `/docker_mirror_cache` for up to 32gb of cached images from all registries
- Map volume `/ca`, the proxy will store the CA certificate here across restarts
- Env `REGISTRIES`: space separated list of registries to cache; no need to include Docker Hub, its already there
@ -71,8 +54,8 @@ Environment="HTTPS_PROXY=http://192.168.66.72:3128/"
EOD
# Get the CA certificate from the proxy and make it a trusted root.
curl http://192.168.66.123:3128/ca.crt > /usr/share/ca-certificates/docker_caching_proxy.crt
echo docker_caching_proxy.crt >> /etc/ca-certificates.conf
curl http://192.168.66.72:3128/ca.crt > /usr/share/ca-certificates/docker_caching_proxy.crt
echo "docker_caching_proxy.crt" >> /etc/ca-certificates.conf
update-ca-certificates --fresh
# Reload systemd
@ -98,3 +81,21 @@ Test your own registry caching and authentication the same way; you don't need `
- If you authenticate to a private registry and pull through the proxy, those images will be served to any client that can reach the proxy, even without authentication. *beware*
- Repeat, this will make your private images very public if you're not careful.
#### Why not use Docker's own registry, which has a mirror feature?
Yes, Docker offers [Registry as a pull through cache](https://docs.docker.com/registry/recipes/mirror/), *unfortunately*
it only covers the DockerHub case. It won't cache images from `quay.io`, `k8s.gcr.io`, `gcr.io`, or any such, including any private registries.
That means that your shiny new Kubernetes cluster is now a bandwidth hog, since every image will be pulled from the
Internet on every Node it runs on, with no reuse.
This is due to the way the Docker "client" implements `--registry-mirror`, it only ever contacts mirrors for images
with no repository reference (eg, from DockerHub).
When a repository is specified `dockerd` goes directly there, via HTTPS (and also via HTTP if included in a
`--insecure-registry` list), thus completely ignoring the configured mirror.
#### Docker itself should provide this.
Yeah. Docker Inc should do it. So should NPM, Inc. Wonder why they don't. 😼