Manage DAGs files

When you create new or modify existing DAG files, it is necessary to deploy them into the environment. This section will describe some basic techniques you can use.

Bake DAGs in Docker image

The recommended way to update your DAGs with this chart is to build a new Docker image with the latest DAG code:

docker build --tag "my-company/airflow:8a0da78" . -f - <<EOF
FROM apache/airflow

COPY ./dags/ \${AIRFLOW_HOME}/dags/

EOF

Note

In Airflow images prior to version 2.0.2, there was a bug that required you to use a bit longer Dockerfile, to make sure the image remains OpenShift-compatible (i.e DAG has root group similarly as other files). In 2.0.2 this has been fixed.

docker build --tag "my-company/airflow:8a0da78" . -f - <<EOF
FROM apache/airflow:2.0.2

USER root

COPY --chown=airflow:root ./dags/ \${AIRFLOW_HOME}/dags/

USER airflow

EOF

Then publish it in the accessible registry:

docker push my-company/airflow:8a0da78

Finally, update the Airflow pods with that image:

helm upgrade --install airflow apache-airflow/airflow \
  --set images.airflow.repository=my-company/airflow \
  --set images.airflow.tag=8a0da78

If you are deploying an image with a constant tag, you need to make sure that the image is pulled every time.

helm upgrade --install airflow apache-airflow/airflow \
  --set images.airflow.repository=my-company/airflow \
  --set images.airflow.tag=8a0da78 \
  --set images.airflow.pullPolicy=Always

Mounting DAGs using Git-Sync sidecar with Persistence enabled

This option will use a Persistent Volume Claim with an access mode of ReadWriteMany. The scheduler pod will sync DAGs from a git repository onto the PVC every configured number of seconds. The other pods will read the synced DAGs. Not all volume plugins have support for ReadWriteMany access mode. Refer Persistent Volume Access Modes for details.

helm upgrade --install airflow apache-airflow/airflow \
  --set dags.persistence.enabled=true \
  --set dags.gitSync.enabled=true
  # you can also override the other persistence or gitSync values
  # by setting the  dags.persistence.* and dags.gitSync.* values
  # Please refer to values.yaml for details

helm upgrade --install airflow apache-airflow/airflow \
  --set dags.persistence.enabled=true \
  --set dags.gitSync.enabled=true
  # you can also override the other persistence or gitSync values
  # by setting the  dags.persistence.* and dags.gitSync.* values
  # Please refer to values.yaml for details

Mounting DAGs using Git-Sync sidecar without Persistence

This option will use an always running Git-Sync sidecar on every scheduler, webserver (if airflowVersion < 2.0.0) and worker pods. The Git-Sync sidecar containers will sync DAGs from a git repository every configured number of seconds. If you are using the KubernetesExecutor, Git-sync will run as an init container on your worker pods.

helm upgrade --install airflow apache-airflow/airflow \
  --set dags.persistence.enabled=false \
  --set dags.gitSync.enabled=true
  # you can also override the other gitSync values
  # by setting the  dags.gitSync.* values
  # Refer values.yaml for details

When using apache-airflow >= 2.0.0, DAG Serialization is enabled by default, hence Webserver does not need access to DAG files, so git-sync sidecar is not run on Webserver.

Mounting DAGs from an externally populated PVC

In this approach, Airflow will read the DAGs from a PVC which has ReadOnlyMany or ReadWriteMany access mode. You will have to ensure that the PVC is populated/updated with the required DAGs (this won’t be handled by the chart). You pass in the name of the volume claim to the chart:

helm upgrade --install airflow apache-airflow/airflow \
  --set dags.persistence.enabled=true \
  --set dags.persistence.existingClaim=my-volume-claim \
  --set dags.gitSync.enabled=false

Mounting DAGs from a private Github repo using Git-Sync sidecar

Create a private repo on Github if you have not created one already.

Then create your ssh keys:

ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

Add the public key to your private repo (under Settings > Deploy keys).

You have to convert the private ssh key to a base64 string. You can convert the private ssh key file like so:

base64 <my-private-ssh-key> -w 0 > temp.txt

Then copy the string from the temp.txt file. You’ll add it to your override-values.yaml next.

In this example, you will create a yaml file called override-values.yaml to override values in the values.yaml file, instead of using --set:

dags:
  gitSync:
    enabled: true
    repo: ssh://git@github.com/<username>/<private-repo-name>.git
    branch: <branch-name>
    subPath: ""
    sshKeySecret: airflow-ssh-secret
extraSecrets:
  airflow-ssh-secret:
    data: |
      gitSshKey: '<base64-converted-ssh-private-key>'

Don’t forget to copy in your private key base64 string.

Finally, from the context of your Airflow Helm chart directory, you can install Airflow:

helm upgrade --install airflow apache-airflow/airflow -f override-values.yaml

If you have done everything correctly, Git-Sync will pick up the changes you make to the DAGs in your private Github repo.

You should take this a step further and set dags.gitSync.knownHosts so you are not susceptible to man-in-the-middle attacks. This process is documented in the production guide.

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