Merge pull request #16801 from aidanhs/aphs-add-socat-t

Update ambassador image, use the socat -t option
This commit is contained in:
Sven Dowideit 2015-10-20 14:24:25 +10:00
commit b826215c57
2 changed files with 40 additions and 35 deletions

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@ -81,42 +81,43 @@ On the Docker host (192.168.1.52) that Redis will run on:
^D
# add redis ambassador
$ docker run -t -i --link redis:redis --name redis_ambassador -p 6379:6379 busybox sh
$ docker run -t -i --link redis:redis --name redis_ambassador -p 6379:6379 alpine:3.2 sh
In the `redis_ambassador` container, you can see the linked Redis
containers `env`:
$ env
/ # env
REDIS_PORT=tcp://172.17.0.136:6379
REDIS_PORT_6379_TCP_ADDR=172.17.0.136
REDIS_NAME=/redis_ambassador/redis
HOSTNAME=19d7adf4705e
SHLVL=1
HOME=/root
REDIS_PORT_6379_TCP_PORT=6379
HOME=/
REDIS_PORT_6379_TCP_PROTO=tcp
container=lxc
REDIS_PORT_6379_TCP=tcp://172.17.0.136:6379
TERM=xterm
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
/ # exit
This environment is used by the ambassador `socat` script to expose Redis
to the world (via the `-p 6379:6379` port mapping):
$ docker rm redis_ambassador
$ sudo ./contrib/mkimage-unittest.sh
$ docker run -t -i --link redis:redis --name redis_ambassador -p 6379:6379 docker-ut sh
$ socat TCP4-LISTEN:6379,fork,reuseaddr TCP4:172.17.0.136:6379
$ CMD="apk update && apk add socat && sh"
$ docker run -t -i --link redis:redis --name redis_ambassador -p 6379:6379 alpine:3.2 sh -c "$CMD"
[...]
/ # socat -t 100000000 TCP4-LISTEN:6379,fork,reuseaddr TCP4:172.17.0.136:6379
Now ping the Redis server via the ambassador:
Now go to a different server:
$ sudo ./contrib/mkimage-unittest.sh
$ docker run -t -i --expose 6379 --name redis_ambassador docker-ut sh
$ socat TCP4-LISTEN:6379,fork,reuseaddr TCP4:192.168.1.52:6379
$ CMD="apk update && apk add socat && sh"
$ docker run -t -i --expose 6379 --name redis_ambassador alpine:3.2 sh -c "$CMD"
[...]
/ # socat -t 100000000 TCP4-LISTEN:6379,fork,reuseaddr TCP4:192.168.1.52:6379
And get the `redis-cli` image so we can talk over the ambassador bridge.
@ -127,8 +128,8 @@ And get the `redis-cli` image so we can talk over the ambassador bridge.
## The svendowideit/ambassador Dockerfile
The `svendowideit/ambassador` image is a small `busybox` image with
`socat` built in. When you start the container, it uses a small `sed`
The `svendowideit/ambassador` image is based on the `alpine:3.2` image with
`socat` installed. When you start the container, it uses a small `sed`
script to parse out the (possibly multiple) link environment variables
to set up the port forwarding. On the remote host, you need to set the
variable using the `-e` command line option.
@ -139,19 +140,21 @@ Will forward the local `1234` port to the remote IP and port, in this
case `192.168.1.52:6379`.
#
#
# first you need to build the docker-ut image
# using ./contrib/mkimage-unittest.sh
# then
# docker build -t SvenDowideit/ambassador .
# docker tag SvenDowideit/ambassador ambassador
# do
# docker build -t svendowideit/ambassador .
# then to run it (on the host that has the real backend on it)
# docker run -t -i --link redis:redis --name redis_ambassador -p 6379:6379 ambassador
# docker run -t -i -link redis:redis -name redis_ambassador -p 6379:6379 svendowideit/ambassador
# on the remote host, you can set up another ambassador
# docker run -t -i --name redis_ambassador --expose 6379 sh
# docker run -t -i -name redis_ambassador -expose 6379 -e REDIS_PORT_6379_TCP=tcp://192.168.1.52:6379 svendowideit/ambassador sh
# you can read more about this process at https://docs.docker.com/articles/ambassador_pattern_linking/
FROM docker-ut
MAINTAINER SvenDowideit@home.org.au
# use alpine because its a minimal image with a package manager.
# prettymuch all that is needed is a container that has a functioning env and socat (or equivalent)
FROM alpine:3.2
MAINTAINER SvenDowideit@home.org.au
RUN apk update && \
apk add socat && \
rm -r /var/cache/
CMD env | grep _TCP= | sed 's/.*_PORT_\([0-9]*\)_TCP=tcp:\/\/\(.*\):\(.*\)/socat TCP4-LISTEN:\1,fork,reuseaddr TCP4:\2:\3 \&/' | sh && top
CMD env | grep _TCP= | sed 's/.*_PORT_\([0-9]*\)_TCP=tcp:\/\/\(.*\):\(.*\)/socat -t 100000000 TCP4-LISTEN:\1,fork,reuseaddr TCP4:\2:\3 \& wait/' | sh

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@ -78,18 +78,20 @@ the `Using cache` message in the console output.
(For more information, see the [Build cache section](../articles/dockerfile_best-practices.md#build-cache)) in the
`Dockerfile` best practices guide:
$ docker build -t SvenDowideit/ambassador .
Uploading context 10.24 kB
Uploading context
Step 1 : FROM docker-ut
---> cbba202fe96b
Step 2 : MAINTAINER SvenDowideit@home.org.au
$ docker build -t svendowideit/ambassador .
Sending build context to Docker daemon 15.36 kB
Step 0 : FROM alpine:3.2
---> 31f630c65071
Step 1 : MAINTAINER SvenDowideit@home.org.au
---> Using cache
---> 51182097be13
Step 3 : CMD env | grep _TCP= | sed 's/.*_PORT_\([0-9]*\)_TCP=tcp:\/\/\(.*\):\(.*\)/socat TCP4-LISTEN:\1,fork,reuseaddr TCP4:\2:\3 \&/' | sh && top
---> 2a1c91448f5f
Step 2 : RUN apk update && apk add socat && rm -r /var/cache/
---> Using cache
---> 1a5ffc17324d
Successfully built 1a5ffc17324d
---> 21ed6e7fbb73
Step 3 : CMD env | grep _TCP= | sed 's/.*_PORT_\([0-9]*\)_TCP=tcp:\/\/\(.*\):\(.*\)/socat -t 100000000 TCP4-LISTEN:\1,fork,reuseaddr TCP4:\2:\3 \& wait/' | sh
---> Using cache
---> 7ea8aef582cc
Successfully built 7ea8aef582cc
When you're done with your build, you're ready to look into [*Pushing a
repository to its registry*](../userguide/dockerrepos.md#contributing-to-docker-hub).