how to run celery with django on openshift 3 - django

Question

What is the easiest way to launch a celery beat and worker process in my django pod?
I'm migrating my Openshift v2 Django app to Openshift v3. I'm using Pro subscription. I'm really a noob on Openshift v3 and docker and containers and kubernetes. I have used this tutorial https://blog.openshift.com/migrating-django-applications-openshift-3/ to migrate my app (which works pretty well).
I'm now struggling on how to start celery. On Openshift 2 I just used an action hook post_start:
source $OPENSHIFT_HOMEDIR/python/virtenv/bin/activate
python $OPENSHIFT_REPO_DIR/wsgi/podpub/manage.py celery worker\
--pidfile="$OPENSHIFT_DATA_DIR/celery/run/%n.pid"\
--logfile="$OPENSHIFT_DATA_DIR/celery/log/%n.log"\
python $OPENSHIFT_REPO_DIR/wsgi/podpub/manage.py celery beat\
--pidfile="$OPENSHIFT_DATA_DIR/celery/run/celeryd.pid"\
--logfile="$OPENSHIFT_DATA_DIR/celery/log/celeryd.log" &
-c 1\
--autoreload &
It is a quite simple setup. It just uses the django database as a message broker. No rabbitMQ or something.
Would a openshift "job" be appropriated for that? Or better use powershift image (https://pypi.python.org/pypi/powershift-image) action commands? But I did not understand how to execute them.
here is the current deployment configuration for my only app "
apiVersion: v1
kind: DeploymentConfig
metadata:
annotations:
openshift.io/generated-by: OpenShiftNewApp
creationTimestamp: 2017-12-27T22:58:31Z
generation: 67
labels:
app: django
name: django
namespace: myproject
resourceVersion: "68466321"
selfLink: /oapi/v1/namespaces/myproject/deploymentconfigs/django
uid: 64600436-ab49-11e7-ab43-0601fd434256
spec:
replicas: 1
selector:
app: django
deploymentconfig: django
strategy:
activeDeadlineSeconds: 21600
recreateParams:
timeoutSeconds: 600
resources: {}
rollingParams:
intervalSeconds: 1
maxSurge: 25%
maxUnavailable: 25%
timeoutSeconds: 600
updatePeriodSeconds: 1
type: Recreate
template:
metadata:
annotations:
openshift.io/generated-by: OpenShiftNewApp
creationTimestamp: null
labels:
app: django
deploymentconfig: django
spec:
containers:
- image: docker-registry.default.svc:5000/myproject/django#sha256:6a0caac773acc65daad2e6ac87695f9f01ae3c99faba14536e0ec2b65088c808
imagePullPolicy: Always
name: django
ports:
- containerPort: 8080
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /opt/app-root/src/data
name: data
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
volumes:
- name: data
persistentVolumeClaim:
claimName: django-data
test: false
triggers:
- type: ConfigChange
- imageChangeParams:
automatic: true
containerNames:
- django
from:
kind: ImageStreamTag
name: django:latest
namespace: myproject
lastTriggeredImage: docker-registry.default.svc:5000/myproject/django#sha256:6a0caac773acc65daad2e6ac87695f9f01ae3c99faba14536e0ec2b65088c808
type: ImageChange
I'm using mod_wsgi-express and this is my app.sh
ARGS="$ARGS --log-to-terminal"
ARGS="$ARGS --port 8080"
ARGS="$ARGS --url-alias /static wsgi/static"
exec mod_wsgi-express start-server $ARGS wsgi/application
Help is very appreciated. Thank you

Answer 1

I have managed to get it working, though I'm not quite happy with it. I will move to a postgreSQL database very soon. Here is what I did:
wsgi_mod-express has an option called service-script which starts an additional process besides the actual app. So I updated my app.sh:
#!/bin/bash
ARGS=""
ARGS="$ARGS --log-to-terminal"
ARGS="$ARGS --port 8080"
ARGS="$ARGS --url-alias /static wsgi/static"
ARGS="$ARGS --service-script celery_starter scripts/startCelery.py"
exec mod_wsgi-express start-server $ARGS wsgi/application
mind the last ARGS=... line.
I created a python script that starts up my celery worker and beat.
startCelery.py:
import subprocess
OPENSHIFT_REPO_DIR="/opt/app-root/src"
OPENSHIFT_DATA_DIR="/opt/app-root/src/data"
pathToManagePy=OPENSHIFT_REPO_DIR + "/wsgi/podpub"
worker_cmd = [
"python",
pathToManagePy + "/manage.py",
"celery",
"worker",
"--pidfile="+OPENSHIFT_REPO_DIR+"/%n.pid",
"--logfile="+OPENSHIFT_DATA_DIR+"/celery/log/%n.log",
"-c 1",
"--autoreload"
]
print(worker_cmd)
subprocess.Popen(worker_cmd, close_fds=True)
beat_cmd = [
"python",
pathToManagePy + "/manage.py",
"celery",
"beat",
"--pidfile="+OPENSHIFT_REPO_DIR+"/celeryd.pid",
"--logfile="+OPENSHIFT_DATA_DIR+"/celery/log/celeryd.log",
]
print(beat_cmd)
subprocess.Popen(beat_cmd)
this was actually working, but I kept receiving a message when I tried to launch the celery worker saying
"Running a worker with superuser privileges when the worker accepts messages serialized with pickle is a very bad idea!
If you really want to continue then you have to set the C_FORCE_ROOT environment variable (but please think about this before you do)."
Eventhough I added these configurations to my settings.py in order to remove pickle serializer, it kept giving me that same error message.
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_ACEEPT_CONTENT = ['json']
I don't know why.
At the end I added C_FORCE_ROOT to my .s2i/enviroment
C_FORCE_ROOT=true
Now it's working, at least I thinks so. My next job will only run in some hours. I'm still open for any further suggestions and tipps.