Airflow 2.2.3 containerized installation

The above simple understanding airflow Concept and usage scenarios of , Passed today Docker Install it. Airflow, In the use of in-depth understanding airflow What are the specific functions .

1Airflow Containerized deployment

Alicloud's host environment ：

• operating system : Ubuntu 20.04.3 LTS
• Kernel version : Linux 5.4.0-91-generic

install docker

install Docker Refer to official documents [1], Pure system , There is no need to uninstall the old version , Because it is a cloud platform , To prevent the configuration from damaging the environment , You can take a snapshot in advance .

 #  to update repo
 sudo apt-get update
 sudo apt-get install \
    ca-certificates \
    curl \
    gnupg \
    lsb-release
    
#  add to docker gpg key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

#  Set up docker stable Warehouse address 
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
  
#  View installable docker-ce edition 
[email protected]:~# apt-cache madison docker-ce
 docker-ce | 5:20.10.12~3-0~ubuntu-focal | https://download.docker.com/linux/ubuntu focal/stable amd64 Packages
 docker-ce | 5:20.10.11~3-0~ubuntu-focal | https://download.docker.com/linux/ubuntu focal/stable amd64 Packages
 docker-ce | 5:20.10.10~3-0~ubuntu-focal | https://download.docker.com/linux/ubuntu focal/stable amd64 Packages
 docker-ce | 5:20.10.9~3-0~ubuntu-focal | https://download.docker.com/linux/ubuntu focal/stable amd64 Packages

#  Install command format 
#sudo apt-get install docker-ce=<VERSION_STRING> docker-ce-cli=<VERSION_STRING> containerd.io
#  Install the specified version 
sudo apt-get install docker-ce=5:20.10.12~3-0~ubuntu-focal docker-ce-cli=5:20.10.12~3-0~ubuntu-focal containerd.io

Optimize Docker To configure

/etc/docker/daemon.json

{
    "data-root": "/var/lib/docker",
    "exec-opts": [
        "native.cgroupdriver=systemd"
    ],
    "registry-mirrors": [
        "https://****.mirror.aliyuncs.com" # Configure some accelerated addresses here , For example, Alibaba cloud and so on ...
    ],
    "storage-driver": "overlay2",
    "storage-opts": [
        "overlay2.override_kernel_check=true"
    ],
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "100m",
        "max-file": "3"
    }
}

Configure the boot itself

systemctl daemon-reload
systemctl enable --now docker.service

Containerization installation Airflow

Database selection

According to the official website , The database recommends using MySQL8+ and postgresql 9.6+, stay Official docker-compose Script [2] It is used in PostgreSQL, So we need to adjust docker-compose.yml The content of

---
version: '3'
x-airflow-common:
  &airflow-common
  # In order to add custom dependencies or upgrade provider packages you can use your extended image.
  # Comment the image line, place your Dockerfile in the directory where you placed the docker-compose.yaml
  # and uncomment the "build" line below, Then run `docker-compose build` to build the images.
  image: ${AIRFLOW_IMAGE_NAME:-apache/airflow:2.2.3}
  # build: .
  environment:
    &airflow-common-env
    AIRFLOW__CORE__EXECUTOR: CeleryExecutor
    AIRFLOW__CORE__SQL_ALCHEMY_CONN: mysql+mysqldb://airflow:[email protected]/airflow #  Replace here with mysql How to connect 
    AIRFLOW__CELERY__RESULT_BACKEND: db+mysql://airflow:[email protected]/airflow #  Replace here with mysql How to connect 
    AIRFLOW__CELERY__BROKER_URL: redis://:[email protected]:6379/0 #  To ensure safety , We are right. redis Authentication enabled , So here xxxx Replace with redis password 
    AIRFLOW__CORE__FERNET_KEY: ''
    AIRFLOW__CORE__DAGS_ARE_PAUSED_AT_CREATION: 'true'
    AIRFLOW__CORE__LOAD_EXAMPLES: 'true'
    AIRFLOW__API__AUTH_BACKEND: 'airflow.api.auth.backend.basic_auth'
    _PIP_ADDITIONAL_REQUIREMENTS: ${_PIP_ADDITIONAL_REQUIREMENTS:-}
  volumes:
    - ./dags:/opt/airflow/dags
    - ./logs:/opt/airflow/logs
    - ./plugins:/opt/airflow/plugins
  user: "${AIRFLOW_UID:-50000}:0"
  depends_on:
    &airflow-common-depends-on
    redis:
      condition: service_healthy
    mysql: #  Change here to mysql service name 
      condition: service_healthy

services:
  mysql:
    image: mysql:8.0.27 #  It is amended as follows mysql Latest image 
    environment:
      MYSQL_ROOT_PASSWORD: bbbb # MySQL root Account and password 
      MYSQL_USER: airflow
      MYSQL_PASSWORD: aaaa # airflow User's password 
      MYSQL_DATABASE: airflow
    command:
      --default-authentication-plugin=mysql_native_password #  Specify the default authentication plug-in 
      --collation-server=utf8mb4_general_ci #  According to the official character set 
      --character-set-server=utf8mb4 #  According to the official character code 
    volumes:
      - /apps/airflow/mysqldata8:/var/lib/mysql #  Persistence MySQL data 
      - /apps/airflow/my.cnf:/etc/my.cnf #  Persistence MySQL The configuration file 
    healthcheck:
      test:  mysql --user=$$MYSQL_USER --password=$$MYSQL_PASSWORD -e 'SHOW DATABASES;' # healthcheck command
      interval: 5s
      retries: 5
    restart: always

  redis:
    image: redis:6.2
    expose:
      - 6379
    command: redis-server --requirepass xxxx # redis-server Turn on password authentication 
    healthcheck:
      test: ["CMD", "redis-cli","-a","xxxx","ping"] # redis Use a password to healthcheck
      interval: 5s
      timeout: 30s
      retries: 50
    restart: always

  airflow-webserver:
    <<: *airflow-common
    command: webserver
    ports:
      - 8080:8080
    healthcheck:
      test: ["CMD", "curl", "--fail", "http://localhost:8080/health"]
      interval: 10s
      timeout: 10s
      retries: 5
    restart: always
    depends_on:
      <<: *airflow-common-depends-on
      airflow-init:
        condition: service_completed_successfully

  airflow-scheduler:
    <<: *airflow-common
    command: scheduler
    healthcheck:
      test: ["CMD-SHELL", 'airflow jobs check --job-type SchedulerJob --hostname "$${HOSTNAME}"']
      interval: 10s
      timeout: 10s
      retries: 5
    restart: always
    depends_on:
      <<: *airflow-common-depends-on
      airflow-init:
        condition: service_completed_successfully

  airflow-worker:
    <<: *airflow-common
    command: celery worker
    healthcheck:
      test:
        - "CMD-SHELL"
        - 'celery --app airflow.executors.celery_executor.app inspect ping -d "[email protected]$${HOSTNAME}"'
      interval: 10s
      timeout: 10s
      retries: 5
    environment:
      <<: *airflow-common-env
      # Required to handle warm shutdown of the celery workers properly
      # See https://airflow.apache.org/docs/docker-stack/entrypoint.html#signal-propagation
      DUMB_INIT_SETSID: "0"
    restart: always
    depends_on:
      <<: *airflow-common-depends-on
      airflow-init:
        condition: service_completed_successfully

  airflow-triggerer:
    <<: *airflow-common
    command: triggerer
    healthcheck:
      test: ["CMD-SHELL", 'airflow jobs check --job-type TriggererJob --hostname "$${HOSTNAME}"']
      interval: 10s
      timeout: 10s
      retries: 5
    restart: always
    depends_on:
      <<: *airflow-common-depends-on
      airflow-init:
        condition: service_completed_successfully

  airflow-init:
    <<: *airflow-common
    entrypoint: /bin/bash
    # yamllint disable rule:line-length
    command:
      - -c
      - |
        function ver() {
          printf "%04d%04d%04d%04d" $${1//./ }
        }
        airflow_version=$$(gosu airflow airflow version)
        airflow_version_comparable=$$(ver $${airflow_version})
        min_airflow_version=2.2.0
        min_airflow_version_comparable=$$(ver $${min_airflow_version})
        if (( airflow_version_comparable < min_airflow_version_comparable )); then
          echo
          echo -e "\033[1;31mERROR!!!: Too old Airflow version $${airflow_version}!\e[0m"
          echo "The minimum Airflow version supported: $${min_airflow_version}. Only use this or higher!"
          echo
          exit 1
        fi
        if [[ -z "${AIRFLOW_UID}" ]]; then
          echo
          echo -e "\033[1;33mWARNING!!!: AIRFLOW_UID not set!\e[0m"
          echo "If you are on Linux, you SHOULD follow the instructions below to set "
          echo "AIRFLOW_UID environment variable, otherwise files will be owned by root."
          echo "For other operating systems you can get rid of the warning with manually created .env file:"
          echo "    See: https://airflow.apache.org/docs/apache-airflow/stable/start/docker.html#setting-the-right-airflow-user"
          echo
        fi
        one_meg=1048576
        mem_available=$$(($$(getconf _PHYS_PAGES) * $$(getconf PAGE_SIZE) / one_meg))
        cpus_available=$$(grep -cE 'cpu[0-9]+' /proc/stat)
        disk_available=$$(df / | tail -1 | awk '{print $$4}')
        warning_resources="false"
        if (( mem_available < 4000 )) ; then
          echo
          echo -e "\033[1;33mWARNING!!!: Not enough memory available for Docker.\e[0m"
          echo "At least 4GB of memory required. You have $$(numfmt --to iec $$((mem_available * one_meg)))"
          echo
          warning_resources="true"
        fi
        if (( cpus_available < 2 )); then
          echo
          echo -e "\033[1;33mWARNING!!!: Not enough CPUS available for Docker.\e[0m"
          echo "At least 2 CPUs recommended. You have $${cpus_available}"
          echo
          warning_resources="true"
        fi
        if (( disk_available < one_meg * 10 )); then
          echo
          echo -e "\033[1;33mWARNING!!!: Not enough Disk space available for Docker.\e[0m"
          echo "At least 10 GBs recommended. You have $$(numfmt --to iec $$((disk_available * 1024 )))"
          echo
          warning_resources="true"
        fi
        if [[ $${warning_resources} == "true" ]]; then
          echo
          echo -e "\033[1;33mWARNING!!!: You have not enough resources to run Airflow (see above)!\e[0m"
          echo "Please follow the instructions to increase amount of resources available:"
          echo "   https://airflow.apache.org/docs/apache-airflow/stable/start/docker.html#before-you-begin"
          echo
        fi
        mkdir -p /sources/logs /sources/dags /sources/plugins
        chown -R "${AIRFLOW_UID}:0" /sources/{logs,dags,plugins}
        exec /entrypoint airflow version
    # yamllint enable rule:line-length
    environment:
      <<: *airflow-common-env
      _AIRFLOW_DB_UPGRADE: 'true'
      _AIRFLOW_WWW_USER_CREATE: 'true'
      _AIRFLOW_WWW_USER_USERNAME: ${_AIRFLOW_WWW_USER_USERNAME:-airflow}
      _AIRFLOW_WWW_USER_PASSWORD: ${_AIRFLOW_WWW_USER_PASSWORD:-airflow}
    user: "0:0"
    volumes:
      - .:/sources

  airflow-cli:
    <<: *airflow-common
    profiles:
      - debug
    environment:
      <<: *airflow-common-env
      CONNECTION_CHECK_MAX_COUNT: "0"
    # Workaround for entrypoint issue. See: https://github.com/apache/airflow/issues/16252
    command:
      - bash
      - -c
      - airflow

  flower:
    <<: *airflow-common
    command: celery flower
    ports:
      - 5555:5555
    healthcheck:
      test: ["CMD", "curl", "--fail", "http://localhost:5555/"]
      interval: 10s
      timeout: 10s
      retries: 5
    restart: always
    depends_on:
      <<: *airflow-common-depends-on
      airflow-init:
        condition: service_completed_successfully

In the official docker-compose.yaml On this basis, only x-airflow-common,MySQL,Redis Related configuration , The next step is to start the container , Before startup , You need to create several persistent directories :

mkdir -p ./dags ./logs ./plugins
echo -e "AIRFLOW_UID=$(id -u)" > .env #  Be careful , Make sure that AIRFLOW_UID It's for ordinary users UID, And ensure that this user has the permission to create these persistent directories 

If you are not an ordinary user , While running the container , Will report a mistake , Can't find airflow modular

docker-compose up airflow-init # Initialize database , And create tables 
docker-compose up -d # establish airflow Containers 

When the status of the container is unhealthy When , To pass the docker inspect $container_name Check the reason for the error , thus airflow The installation of is complete .

Reference material

[1] Install Docker Engine on Ubuntu: https://docs.docker.com/engine/install/ubuntu/

[2] official docker-compose.yaml: https://airflow.apache.org/docs/apache-airflow/2.2.3/docker-compose.yaml