Tag Archives: devops

Docker tips

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:

https://docs.docker.com/engine/docker-overview/

https://training.docker.com/

https://veggiemonk.github.io/awesome-docker/

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

Ansible tips

Este post se limita a incluir algunas notas sobre el uso de Ansible y en particular sobre la realización de un tutorial paso a paso sobre la aplicación del mismo, incluyendo los conceptos más básicos.

Inventory file

[ansiblet1@svprac02 step-01]$ cat hosts
host0.example.org ansible_host=192.168.33.10 ansible_user=root
host1.example.org ansible_host=192.168.33.11 ansible_user=root
host2.example.org ansible_host=192.168.33.12 ansible_user=root

[ansiblet1@svprac02 step-01]$ cat hosts

host0.example.org ansible_host=192.168.33.10 ansible_user=root

host1.example.org ansible_host=192.168.33.11 ansible_user=root

host2.example.org ansible_host=192.168.33.12 ansible_user=root

Ejecuta comandos

[ansiblet1@svprac02 step-01]$ ansible -m ping all -i hosts
host1.example.org | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
host0.example.org | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
host2.example.org | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

[ansiblet1@svprac02 step-01]$ ansible -m ping all -i hosts

host1.example.org | SUCCESS => {

"changed": false,

"ping": "pong"

}

host0.example.org | SUCCESS => {

"changed": false,

"ping": "pong"

}

host2.example.org | SUCCESS => {

"changed": false,

"ping": "pong"

}

Módulos (plugins)

[ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m copy -a 'src=/etc/motd dest=/tmp/' host0.example.org
[ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m shell -a 'grep DISTRIB_RELEASE /etc/lsb-release' all

1 2	[ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m copy -a 'src=/etc/motd dest=/tmp/' host0.example.org [ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m shell -a 'grep DISTRIB_RELEASE /etc/lsb-release' all

Obtiene información sobre los nodos del inventario

[ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m setup host0.example.org
[ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m setup -a 'filter=ansible_memtotal_mb' all

1 2	[ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m setup host0.example.org [ansiblet1@svprac02 ansible-tuto]$ ansible -i step-02/hosts -m setup -a 'filter=ansible_memtotal_mb' all

Fichero de inventario, agrupaciones

[ubuntu]
host0.example.org

[debian]
host[1:2].example.org

[linux:children]
ubuntu
debian

[ubuntu]

host0.example.org

[debian]

host[1:2].example.org

[linux:children]

ubuntu

debian

Variables en fichero de inventario

[ubuntu]
host0.example.org ansible_host=192.168.0.12 ansible_port=2222

1 2	[ubuntu] host0.example.org ansible_host=192.168.0.12 ansible_port=2222

Playbooks

[ansiblet1@svprac02 step-04]$ cat apache.yml
    - hosts: web
      tasks:
        - name: Installs apache web server
          apt: pkg=apache2 state=installed update_cache=true

[ansiblet1@svprac02 step-04]$ cat apache.yml

- hosts: web

tasks:

- name: Installs apache web server

apt: pkg=apache2 state=installed update_cache=true

Registra resultado de tareas y ejecuta en función de su valor

- name: Check that our config is valid
  command: apache2ctl configtest
  register: result
  ignore_errors: True

- name: Rolling back - Restoring old default virtualhost
  command: a2ensite 000-default
  when: result|failed

- name: Rolling back - Removing out virtualhost
  command: a2dissite awesome-app
  when: result|failed

- name: Rolling back - Ending playbook
  fail: msg="Configuration file is not valid. Please check that before re-running the playbook."
  when: result|failed

- name: Check that our config is valid

command: apache2ctl configtest

ignore_errors: True

- name: Rolling back - Restoring old default virtualhost

command: a2ensite 000-default

when: result|failed

- name: Rolling back - Removing out virtualhost

command: a2dissite awesome-app

when: result|failed

- name: Rolling back - Ending playbook

fail: msg="Configuration file is not valid. Please check that before re-running the playbook."

when: result|failed

Iteraciones en playbooks

- name: Installs necessary packages
  apt: pkg={{ item }} state=latest
  with_items:
        - apache2
        - libapache2-mod-php5
        - git

- name: Installs necessary packages

apt: pkg={{ item }} state=latest

with_items:

- apache2

- libapache2-mod-php5

- git

Usar tags en playbooks

- name: Deploy our awesome application
  git: repo=https://github.com/leucos/ansible-tuto-demosite.git dest=/var/www/awesome-app
  tags: deploy

- name: Deploy our awesome application

git: repo=https://github.com/leucos/ansible-tuto-demosite.git dest=/var/www/awesome-app

tags: deploy

[ansiblet1@svprac02 step-08]$ ansible-playbook -i hosts apache.yml -t deploy

1	[ansiblet1@svprac02 step-08]$ ansible-playbook -i hosts apache.yml -t deploy

Jinja templates

listen cluster
    bind {{ ansible_eth1['ipv4']['address'] }}:80
    mode http
    stats enable
    balance roundrobin
{% for backend in groups['web'] %}
    server {{ hostvars[backend]['ansible_hostname'] }} {{ hostvars[backend]['ansible_eth1']['ipv4']['address'] }} check port 80
{% endfor %}

listen cluster

bind {{ ansible_eth1['ipv4']['address'] }}:80

mode http

stats enable

balance roundrobin

{% for backend in groups['web'] %}

server {{ hostvars[backend]['ansible_hostname'] }} {{ hostvars[backend]['ansible_eth1']['ipv4']['address'] }} check port 80

{% endfor %}

And in the playbook

template: src=templates/haproxy.cfg.j2 dest=/etc/haproxy/haproxy.cfg mode=0640 owner=root group=root

1	template: src=templates/haproxy.cfg.j2 dest=/etc/haproxy/haproxy.cfg mode=0640 owner=root group=root

Lanza varios playbooks

$ ansible-playbook -i step-10/hosts step-10/apache.yml step-10/haproxy.yml

1	$ ansible-playbook -i step-10/hosts step-10/apache.yml step-10/haproxy.yml

Variables para hosts y para grupos

[ansiblet1@svprac02 step-11]$ ll
total 20
-rw-r--r--. 1 ansiblet1 ansiblet 1624 Jul  5 18:54 apache.yml
drwxr-xr-x. 2 ansiblet1 ansiblet   25 Jul  5 18:54 files
drwxr-xr-x. 2 ansiblet1 ansiblet   21 Jul  5 18:54 group_vars
-rw-r--r--. 1 ansiblet1 ansiblet  576 Jul  5 18:54 haproxy.yml
-rw-r--r--. 1 ansiblet1 ansiblet  206 Jul  5 18:54 hosts
drwxr-xr-x. 2 ansiblet1 ansiblet   81 Jul  5 18:54 host_vars
-rw-r--r--. 1 ansiblet1 ansiblet 5246 Jul  5 18:54 README.md
drwxr-xr-x. 2 ansiblet1 ansiblet   28 Jul  5 18:54 templates

[ansiblet1@svprac02 step-11]$ cat group_vars/haproxy
haproxy_check_interval: 3000
haproxy_stats_socket: /tmp/sock

[ansiblet1@svprac02 step-11]$ ll

total 20

-rw-r--r--. 1 ansiblet1 ansiblet 1624 Jul 5 18:54 apache.yml

drwxr-xr-x. 2 ansiblet1 ansiblet 25 Jul 5 18:54 files

drwxr-xr-x. 2 ansiblet1 ansiblet 21 Jul 5 18:54 group_vars

-rw-r--r--. 1 ansiblet1 ansiblet 576 Jul 5 18:54 haproxy.yml

-rw-r--r--. 1 ansiblet1 ansiblet 206 Jul 5 18:54 hosts

drwxr-xr-x. 2 ansiblet1 ansiblet 81 Jul 5 18:54 host_vars

-rw-r--r--. 1 ansiblet1 ansiblet 5246 Jul 5 18:54 README.md

drwxr-xr-x. 2 ansiblet1 ansiblet 28 Jul 5 18:54 templates

[ansiblet1@svprac02 step-11]$ cat group_vars/haproxy

haproxy_check_interval: 3000

haproxy_stats_socket: /tmp/sock

Se pueden usar en templates

{% if haproxy_stats_socket %}
    stats socket {{ haproxy_stats_socket }}
{% endif %}

{% if haproxy_stats_socket %}

stats socket {{ haproxy_stats_socket }}

{% endif %}

Roles

[ansiblet1@svprac02 step-12]$ ll roles/apache/
total 0
drwxr-xr-x. 2 ansiblet1 ansiblet 25 Jul  5 18:54 files
drwxr-xr-x. 2 ansiblet1 ansiblet 22 Jul  5 18:54 handlers
drwxr-xr-x. 2 ansiblet1 ansiblet 22 Jul  5 18:54 tasks

[ansiblet1@svprac02 step-12]$ ll roles/apache/tasks/
total 4
-rw-r--r--. 1 ansiblet1 ansiblet 1221 Jul  5 18:54 main.yml

[ansiblet1@svprac02 step-12]$ ll roles/apache/

total 0

drwxr-xr-x. 2 ansiblet1 ansiblet 25 Jul 5 18:54 files

drwxr-xr-x. 2 ansiblet1 ansiblet 22 Jul 5 18:54 handlers

drwxr-xr-x. 2 ansiblet1 ansiblet 22 Jul 5 18:54 tasks

[ansiblet1@svprac02 step-12]$ ll roles/apache/tasks/

total 4

-rw-r--r--. 1 ansiblet1 ansiblet 1221 Jul 5 18:54 main.yml

Se lanzan los roles desde el playbook principal

[ansiblet1@svprac02 step-12]$ cat site.yml
- hosts: web
  roles:
    - { role: apache }

- hosts: haproxy
  roles:
    - { role: haproxy }

[ansiblet1@svprac02 step-12]$ cat site.yml

- hosts: web

roles:

- { role: apache }

- hosts: haproxy

roles:

- { role: haproxy }

Estructura de los roles

Referencias

https://www.ansible.com/get-started

https://www.ansible.com/how-ansible-works

https://www.ansible.com/webinars-training/introduction-to-ansible

El Recetario

Recetas Java y más

Tag Archives: devops

Docker tips

Containers

Images

Swarm stack

Persist de data

Docker network drivers (default and created)

Ansible tips

Inventory file

Ejecuta comandos

Módulos (plugins)

Fichero de inventario, agrupaciones

Playbooks

Jinja templates

Variables para hosts y para grupos

Roles

Estructura de los roles

Referencias