No such file or directory /airflow/xcom/return.jso

Question

created an image contain /airflow/xcom/return.json with chmod +x on all sub-dir Since the log show it cannot find file or directory(tried chmod +x)

strtpodbefore = KubernetesPodOperator(namespace='rguonew',
                                    image="mydockerimage",
                                    name="fail",
                                    image_pull_policy="Always",
                                    task_id="failing-task",
                                    get_logs= True,
                                    xcom_push=True,
                                    dag=dag
                                    )'

Here is the log

[2019-03-18 20:32:07,007] {logging_mixin.py:95} INFO - [2019-03-18 
 20:32:07,007] {pod_launcher.py:166} INFO - Running command... cat 
/airflow/xcom/return.json
[2019-03-18 20:32:07,007] {logging_mixin.py:95} INFO - 
[2019-03-18 20:32:07,026] {logging_mixin.py:95} INFO - [2019-03-18 
20:32:07,026] {pod_launcher.py:173} INFO - cat: can't open 
 '/airflow/xcom/return.json': No such file or directory
[2019-03-18 20:32:07,026] {logging_mixin.py:95} INFO - 
[2019-03-18 20:32:07,026] {logging_mixin.py:95} INFO - [2019-03-18 
 20:32:07,026] {pod_launcher.py:166} INFO - Running command... kill -s 
 SIGINT 1
[2019-03-18 20:32:07,026] {logging_mixin.py:95} INFO - 
[2019-03-18 20:32:07,067] {models.py:1788} ERROR - Pod Launching 
failed: Failed to extract xcom from pod: fail-e18e3dac

So tried with this way it works, but it means its assigns the xcom json from outside but not from the image

 return_value = '{"foo": "bar"\n, "buzz": 2}'
 strtpodbefore = KubernetesPodOperator(namespace='rguonew',
                                image="python:3.6.6-stretch",
                                cmds=["bash", "-cx"],
                                name="fail",
                                task_id="failing-task",
                                arguments=['echo \'{}\' > 
 /airflow/xcom/return.json'.format(return_value)],
                                get_logs= True,
                                xcom_push=True,
                                dag=dag
                                )

so i tried the final solution with doing an extra argument but still doesnt work, the first command get no such directory return

strtpodbefore = KubernetesPodOperator(namespace='rguonew',
                                    image="myimages",
                                    name="fail",
                                    image_pull_policy="Always",
                                    cmds=["bash", "-cx"],
                                    arguments=['echo \'{}\' > 
/airflow/xcom/return.json'.format(return_value)],
                                    task_id="failing-task",
                                    get_logs= True,
                                    xcom_push=True,
                                    dag=dag
                                    )

Answer 1

When you set the xcom_push=True, a sidecar container will be created along with your executor container. The sidecar container will read the executor's /airflow/xcom/return.json, so you actually need to write to this from the executor container as you have done in the 2nd example.

See here: https://stackoverflow.com/a/53568710/10675601

When we were working on our pod xcom, there were also some issues related to RBAC that you need to set: Airflow k8s operator xcom - Handshake status 403 Forbidden