helm: fix graceful shutdown for reana-server

Avoid using `/bin/sh -c` to run uwsgi, as that breaks signal
propagation.

Closes reanahub/reana-job-controller#347

CHANGES.rst

@@ -17,6 +17,7 @@ Version 0.9.1 (UNRELEASED)
  - Fixes uWSGI memory consumption on systems with very high allowed number of open files.
  - Fixes cronjob failures due to database connection issues when REANA is deployed with non-default namespace or prefix.
  - Fixes ``ingress.enabled`` option to correctly enable or disable the creation of Ingresses.
+ - Fixes graceful shutdown for reana-server and reana-workflow-controller.
  - Adds new configuration options ``login`` and ``secrets.login`` for configuring Keycloak SSO login with third-party authentication services.
 - Developers:
  - Fixes ``cluster-deploy``, ``cluster-undeploy`` and ``client-setup-environment`` commands when using custom instance name or kubernetes namespace.

helm/reana/templates/reana-server.yaml

@@ -43,8 +43,8 @@ spec:
  tty: true
  stdin: true
  {{- else }}
- command: ["/bin/sh", "-c"]
- args: ["uwsgi --ini /var/reana/uwsgi/uwsgi.ini"]
+ # do not use "/bin/sh -c" here as that breaks signal propagation
+ command: ["uwsgi", "--ini", "/var/reana/uwsgi/uwsgi.ini"]
  {{- end }}
  volumeMounts:
  {{- if .Values.debug.enabled }}