docker | El Recetario

En este post se incluyen una revisión muy sencilla y un conjunto de comandos y acciones relacionadas con el uso de Docker. Para más información, consultar en:

Containers

Running a container

docker container run hello-world

1	docker container run hello-world

Pull an image from the Docker registry

docker image pull alpine

1	docker image pull alpine

List the content of the downloaded Docker images

docker image ls

1	docker image ls

Run commands on a launched container

docker container run alpine ls -l
</code><code>docker container run alpine echo "hello from alpine"

1 2	docker container run alpine ls -l </code><code>docker container run alpine echo "hello from alpine"

Launch container in interactive mode

docker container run -it alpine /bin/sh

1	docker container run -it alpine /bin/sh

List running containers (and ran)

docker container ls
docker container ls -a

1 2	docker container ls docker container ls -a

Images

Inspect an image

docker image inspect alpine

1	docker image inspect alpine

Download and run image in one goal

docker container run -d seqvence/static-site

1	docker container run -d seqvence/static-site

Stop and remove container

docker container stop &lt;container-id&gt;
docker container rm   &lt;container-id&gt;
docker container rm -f  &lt;container-id&gt;

docker container stop <container-id>

docker container rm <container-id>

docker container rm -f <container-id>

Run container in detached mode and provide details

docker container run --name static-site -e AUTHOR="Your Name" -d -P seqvence/static-site 
docker container run --name static-site -e AUTHOR="Your Name" -d –p 8888:80 seqvence/static-site

1 2	docker container run --name static-site -e AUTHOR="Your Name" -d -P seqvence/static-site docker container run --name static-site -e AUTHOR="Your Name" -d –p 8888:80 seqvence/static-site

--name --> Name to the container

-e --> Pass variables

-d --> detached mode

-P --> publish ports to docker container host

-p 8888:80 --> Relate port 80 to 8888 in docker host

Image types

Base

OS images

Child

Based on a base image

Official

Certified by Docker

User

User created images (from base, usually)

Create a new image (user image)

Create a docker file (Dockerfile)

# our base image
FROM alpine:edge
# Install python and pip
RUN apk add --update py2-pip
# install Python modules needed by the Python app
COPY requirements.txt /usr/src/app/
RUN pip install --no-cache-dir -r /usr/src/app/requirements.txt 
# copy files required for the app to run
COPY app.py /usr/src/app/
COPY templates/index.html /usr/src/app/templates/
# tell the port number the container should expose
EXPOSE 5000
# run the application
CMD ["python", "/usr/src/app/app.py"]

# our base image

FROM alpine:edge

# Install python and pip

RUN apk add --update py2-pip

# install Python modules needed by the Python app

COPY requirements.txt /usr/src/app/

RUN pip install --no-cache-dir -r /usr/src/app/requirements.txt

# copy files required for the app to run

COPY app.py /usr/src/app/

COPY templates/index.html /usr/src/app/templates/

# tell the port number the container should expose

EXPOSE 5000

# run the application

CMD ["python", "/usr/src/app/app.py"]

Build the image

docker image build -t <YOUR_USERNAME>/myfirstapp .

1	docker image build -t <YOUR_USERNAME>/myfirstapp .

-t –> image tag

. –> directory where Dockerfile is present

Swarm stack

Init swarm manager

docker swarm init --advertise-addr $(hostname -i)

1	docker swarm init --advertise-addr $(hostname -i)

Docker compose files (docker-compose.yml)

version:<code> </code>"3"
</code>services:<code></code><code>
</code>    web:<code></code><code>
      </code># replace username/repo:tag with your name and image details<code></code><code>
      </code>image:<code> </code>username/repository:tag<code></code><code>
      </code>deploy:<code>
        replicas:<code> </code>5
</code>resources:
          </code>limits:<code></code><code>
            </code>cpus:<code> </code>"0.1"<code></code><code>
            </code>memory:<code> </code>50M<code>
        restart_policy:<code></code><code>
          </code>condition:<code> </code>on-failure<code></code><code>
       </code>ports:<code></code><code>
         </code>-<code> </code>"80:80"<code></code><code>
       </code>networks:<code></code><code>
         </code>-<code> </code>webnet
</code>networks:<code></code><code>
       </code>webnet:<code>

version:<code> </code>"3"

</code>services:<code></code><code>

</code> web:<code></code><code>

</code># replace username/repo:tag with your name and image details<code></code><code>

</code>image:<code> </code>username/repository:tag<code></code><code>

</code>deploy:<code>

replicas:<code> </code>5

</code>resources:

</code>limits:<code></code><code>

</code>cpus:<code> </code>"0.1"<code></code><code>

</code>memory:<code> </code>50M<code>

restart_policy:<code></code><code>

</code>condition:<code> </code>on-failure<code></code><code>

</code>ports:<code></code><code>

</code>-<code> </code>"80:80"<code></code><code>

</code>networks:<code></code><code>

</code>-<code> </code>webnet

</code>networks:<code></code><code>

</code>webnet:<code>

Deploy the stack

docker stack deploy -c docker-compose.yml &lt;stack_name&gt;
docker-compose up -d

docker stack deploy -c docker-compose.yml <stack_name>

docker-compose up -d

Join swarm

docker swarm join &lt;ip&gt;:&lt;port&gt;

1 2	docker swarm join <ip>:<port>

List nodes

docker node ls

1 2	docker node ls

List services

docker stack services &lt;stack_name&gt;
docker-compose ps

1 2	docker stack services <stack_name> docker-compose ps

Inspect services

docker service inspect &lt;service_name&gt;

1	docker service inspect <service_name>

Scale up or down the service

docker service scale &lt;service_name&gt;=&lt;service_number&gt;
docker-compose scale &lt;service_name&gt;=&lt;service_number&gt;
docker service update --replicas &lt;service_number&gt; &lt;service_name&gt;

docker service scale <service_name>=<service_number>

docker-compose scale <service_name>=<service_number>

docker service update --replicas <service_number> <service_name>

Disable/Enable nodes

docker node update --availability drain &lt;node_name&gt;
docker node update --availability active &lt;node_name&gt;
docker node inspect &lt;node_name&gt; --pretty

docker node update --availability drain <node_name>

docker node update --availability active <node_name>

docker node inspect <node_name> --pretty

List deployed tasks

docker stack ps &lt;stack_name&gt;

1	docker stack ps <stack_name>

Leave the swarm

docker swarm leave

1	docker swarm leave

Remove stack

docker swarm rm &lt;stack_name&gt;</code> 
docker-compose down

1 2	docker swarm rm <stack_name></code> docker-compose down

Inspect the container

docker container inspect &lt;container_name&gt; 
docker container inspect --format "{{ .Config.Hostname }}" &lt;container_name&gt;

1 2	docker container inspect <container_name> docker container inspect --format "{{ .Config.Hostname }}" <container_name>

Persist de data

In the host, via de docker-compose file:

redis:<code>
  image:<code> </code>redis<code>
  ports:<code>
    -<code> </code>"6379:6379"<code></code><code>
  </code>volumes:<code>
    -<code> </code>./data:/data

redis:<code>

image:<code> </code>redis<code>

ports:<code>

-<code> </code>"6379:6379"<code></code><code>

</code>volumes:<code>

-<code> </code>./data:/data

Via de Docker file:

VOLUME ["/data"]

1	VOLUME ["/data"]

The /data will be created on the host as well:

docker container inspect -f "{{ json .Mounts }}"  c2 | python -m json.tool

1	docker container inspect -f "{{ json .Mounts }}" c2 \| python -m json.tool

[
  {
    "Destination": "/data",
    "Driver": "local",
    "Mode": "",
    "Name": "2f5b7c6b77494934293fc7a09198dd3c20406f05272121728632a4aab545401c",
    "Propagation": "",
    "RW": true,
    "Source": "/graph/volumes/2f5b7c6b77494934293fc7a09198dd3c20406f05272121728632a4aab545401c/_data",
    "Type": "volume"
  }
]

[

{

"Destination": "/data",

"Driver": "local",

"Mode": "",

"Name": "2f5b7c6b77494934293fc7a09198dd3c20406f05272121728632a4aab545401c",

"Propagation": "",

"RW": true,

"Source": "/graph/volumes/2f5b7c6b77494934293fc7a09198dd3c20406f05272121728632a4aab545401c/_data",

"Type": "volume"

}

]

Using the –v option

Create and mount
Mount

docker container run --name c3 -d -v /data alpine sh -c 'ping 8.8.8.8 &gt; /data/ping.txt'
</code><code>docker container run -v HOST_PATH:CONTAINER_PATH [OPTIONS] IMAGE [CMD]

1 2	docker container run --name c3 -d -v /data alpine sh -c 'ping 8.8.8.8 > /data/ping.txt' </code><code>docker container run -v HOST_PATH:CONTAINER_PATH [OPTIONS] IMAGE [CMD]

Using the Volume API

Create the volumen on the host

docker volume create --name &lt;vol_name&gt;
docker volume inspect html
[
  {
    "Driver": "local",
    "Labels": {},
    "Mountpoint": "/graph/volumes/html/_data",
    "Name": "html",
    "Options": {},
    "Scope": "local"
  }
]

docker volume create --name <vol_name>

docker volume inspect html

[

{

"Driver": "local",

"Labels": {},

"Mountpoint": "/graph/volumes/html/_data",

"Name": "html",

"Options": {},

"Scope": "local"

}

]

Mount it and use it within a container

docker container run --name www -d -p 8080:80 -v html:/usr/share/nginx/html nginx

1	docker container run --name www -d -p 8080:80 -v html:/usr/share/nginx/html nginx

Docker network drivers (default and created)

Bridge support only a single node
Overlay support multiple nodes

docker network ls

1	docker network ls

Create overlay network

docker network create -d overlay &lt;network_name&gt;

1	docker network create -d overlay <network_name>

Inspect network

docker network inspect &lt;network_name&gt;

1	docker network inspect <network_name>

Run container within network

docker run -d --net=&lt;network_name&gt; --name &lt;container_name&gt; &lt;image_name&gt;

1 2	docker run -d --net=<network_name> --name <container_name> <image_name>

By default, bridge network driver is used

docker run -d --name <container_name> <image_name> <command>

1	docker run -d --name <container_name> <image_name> <command>

Connect an existent container to an existent network

docker network connect &lt;network_name&gt; &lt;container_name&gt;

1	docker network connect <network_name> <container_name>

Service discovery

docker ps

docker ps

Docker info

docker info

1	docker info

Use Docker API to communicate with Docker

docker-machine env <node_name> --> apply docker commands on that node (alternative, use DOCKER_HOST variable)

1	docker-machine env <node_name> --> apply docker commands on that node (alternative, use DOCKER_HOST variable)

Upgrade/downgrade to/from manager

docker node promote <node_name_or_id>
docker node demote <node_name_or_id>

1 2	docker node promote <node_name_or_id> docker node demote <node_name_or_id>

Docker swarm visualizer

http://jpetazzo.github.io/orchestration-workshop/#118

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