Situation:
I have a docker swarm with two agents. The docker swarm main daemon runs on my manager host (docker-machine example setup) with --strategy random option.
Steps:
I build a new docker image using the docker swarm manager connection
docker -H tcp://$(docker-machine ip manager):3376 build -t test123 .
I startup multiple containers using the manager connection
docker -H tcp://$(docker-machine ip manager):3376 run -d test123 sleep 20
docker -H tcp://$(docker-machine ip manager):3376 run -d test123 sleep 20
docker -H tcp://$(docker-machine ip manager):3376 run -d test123 sleep 20
docker -H tcp://$(docker-machine ip manager):3376 run -d test123 sleep 20
The docker container is always executed on the host which was also used for building the image.
Is there a way to automatically distribute the build image to other hosts?
I know that i could use a docker registry and just push and pull the image but i want to avoid this.
Another solution i found was to save the image to a tgz and import it. A import on a docker-swarm host (manager) automatically distributes the image to all agents. (at least this was what i observed)
Is there maybe another option?
Related
I'm looking at documentation here, and see the following line:
$ docker run -it --network some-network --rm redis redis-cli -h some-redis
What should go in the --network some-network field? My docker run command in the field before did default port mapping of docker run -d -p 6379:6379, etc.
I'm starting my redis server with default docker network configuration, and see this is in use:
$ docker container ls
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
abcfa8a32de9 redis "docker-entrypoint.s…" 19 minutes ago Up 19 minutes 0.0.0.0:6379->6379/tcp some-redis
However, using the default bridge network produces:
$ docker run -it --network bridge --rm redis redis-cli -h some-redis
Could not connect to Redis at some-redis:6379: Name or service not known
Ignore the --network bridge command and use:
docker exec -it some-redis redis-cli
Docker includes support for networking containers through the use of network drivers. By default, Docker provides two network drivers for you, the bridge and the overlay drivers. You can also write a network driver plugin so that you can create your own drivers but that is an advanced task.
Read more here.
https://docs.docker.com/engine/tutorials/networkingcontainers/
https://docs.docker.com/v17.09/engine/userguide/networking/
You need to run
docker network create some-network
It doesn't matter what name some-network is, just so long as the Redis server, your special CLI container, and any clients talking to the server all use the same name. (If you're using Docker Compose this happens for you automatically and the network will be named something like directoryname_default; use docker network ls to find it.)
If your Redis server is already running, you can use docker network connect to attach the existing container to the new network. This is one of the few settings you're able to change after you've created a container.
If you're just trying to run a client to talk to this Redis, you don't need Docker for this at all. You can install the Redis client tools locally and run redis-cli, pointing at your host's IP address and the first port in the docker run -p option. The Redis wire protocol is simple enough that you can also use primitive tools like nc or telnet as well.
In my docker-compose , i have 2 containers .
How to make this 2 containers access each other as they installed in one host without containers .
How they can see each other and their file systems
To allow inter-container communication create a common bridge network, and put both containers into the same network. The build phase assuming nothing needs to "talk" to each other does not need the --network switch.
docker network create jointops
docker build --network jointops -t srv1 /srv1
docker build --network jointops -t srv2 /srv2
docker run --network jointops -d -t srv1
docker run --network jointops -d -t srv2
To check both machines are on the same network now issue the command
docker network inspect jointops
You should see both machines having an IP Allocation.
Ok... so how do they communicate ?
The bridge network - jointops by default will perform dns-resolution
So if srv1 has something like
curl -c http://srv2/bla/bla/bla
This will be resolved correctly.
Regarding Shared Data access ..
Do not run 2 apps in 1 container
Instead
create a docker volume
run 2 separate containers
each container can connect to the same volume
See here for inter-container communication. Each container encapsulates its contents, so use ports for communication instead of trying to just openly expose the full filesystem of one container to another.
If both applications need access to the same filesystem, consider running both in the same container. That is supported.
I have a setup which runs my Docker container like this.
run-docker.sh
docker build -t wordpress-gcloud
container=$(docker run -d wordpress-gcloud)
ipOfContainer=$(docker inspect "$container" | jq -r '.[0].NetworkSettings.IPAddress')
But now I have setup a Docker Swarm (1 manager + 2 workers).
How should I convert the above bash script to run the container on the swarm?
Typically, you can access your Swarm cluster via Swarm APIs, which is similar with Docker API. To access Swarm APIs, you can use -H parameter with docker commands. For example, if you have a swarm manager running on your local machine, and the port number is 3376, then you can get your swarm cluster info with:
docker -H 127.0.0.1:3376 info
You can also inspect the swarm cluster containers by:
docker -H 127.0.0.1:3376 inspect <container ID>
More details about communciate with Swarm cluster can be found here: https://docs.docker.com/swarm/install-manual/#/step-6-communicate-with-the-swarm
But in your case, I think that docker build command could be a problem. In my understanding, Swarm will find a random node from your cluster to execute this docker build process, so if the Dockerfile is not existing on the node where docker build has been executed, you will get error. My idea is to consider to build your image in a certain place, and push the image to a image registry, then pull and run the image in any place you want.
Our jenkins deploys/builds code in a docker container. Every time Jenkins deploys code, it does so in different instance of docker container. How do I know IP address of that container along with port id? Immediately after deployment I want to run my Build Validation test against the application residing in that docker container.
Any insight would be appreciated.
You need to specify -p in docker run and then use docker inspect to grab the port:
docker run -d -p 80 --name app crramirez/limesurvey
export THEPORT=`docker inspect --format='{{(index (index .NetworkSettings.Ports "80/tcp") 0).HostPort}}' app`
Then you call your application: wget http://localhost:${THEPORT}
All of this is necessary if you have many containers running concurrently. But if you only deploy one container at time. You only need to delete the previous container and do a docker run -d -p 80:80 call your application using your port wget http://localhost:80
Regards
I finished this documentation:
https://docs.docker.com/swarm/install-w-machine/
It works fine.
Now I tried to setup this EC2 instances by following this documentation:
https://docs.docker.com/swarm/install-manual/
I am in Step 4. Set up a discovery backend
I cannot understand the steps what I need to do further.
I created 5 nodes in EC2: manager0, manager1, consul0, node0, node1. Now I need to know how to setup service discovery with swarm.
In that document they ask us to connect manager0 and consul0 then ifconfig, then they given as etc0 instance. I don't know where this is coming from.
Ultimately I need to know where (in which node?) to run this command:
$ docker run -d -p 8500:8500 --name=consul progrium/consul -server -bootstrap
Any suggestion for me How to clear this step?
Consul will run on the consul0 server you created. So basically you first need to be able to run docker on worker0 and worker1 remotely, this is step 3. A better way of doing this is editing the daemon directly with the command:
sudo echo 'DOCKER_OPTS="-H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock"' > /etc/default/docker`
Then restart docker. Afterwards you will find that you can run docker remotely from master0, master1 or any other instance behind your firewall with docker commands that start with:
docker -H $WORKER0_IPADDRESS:2375
For example if your workers ip address was 1.2.3.4 this would run the docker ps command remotely:
docker -H 1.2.3.4:2375 ps
This is what swarm runs on. Then start up your consul server with the command you want to run, you got that one right and thats it you wont do anything else with the consul0 server except use its IP address when you run your swarm commands.
So if $CONSUL0 represented the IP address of your consul server this is how you would set up the rest of swarm. If you ran each of them on the local machine of each node:
On consul0:
docker run -d -p 8500:8500 --restart=unless-stopped --name=consul progrium/consul -server -bootstrap
On master0 and master1:
docker run --name=master -d -p 4000:4000 swarm manage -H :4000 --replication --advertise $(hostname -i):4000 consul://$CONSUL0:8500
On worker0 and worker1:
docker run -d --name=worker swarm join --advertise=$(hostname -i):2375 consul://$CONSUL0:8500/