Service with multiple targetPort needs routes with distinct names

Solution Unverified - Updated -

Environment

  • Red Hat OpenShift Container Platform (RHOCP) 4

Issue

  • Route log reports fatal errors related with the backend server named as it is already defined

Resolution

  • Configure the route with the correct target port of the service

    • For service with multiple port configuration:
    apiVersion: v1
kind: Service
metadata:
  name: httpd
  namespace: webserver
spec:
  ports:
  - name: 8080-tcp
    port: 8080
    protocol: TCP
    targetPort: 8080
  - name: 18080-tcp
    port: 18080
    protocol: TCP
    targetPort: 18080
 selector:
   deployment: httpd
    • The route configuration should be like:
    apiVersion: route.openshift.io/v1
kind: Route
metadata:
  labels:
    app: httpd
  name: httpd-mon
  namespace: webserver
spec:
   host: httpd-mon-webserver.apps.ipi-default.testipi.com
   port:
     targetPort: 18080-tcp
   to:
     kind: Service
     name: httpd-mon

    apiVersion: route.openshift.io/v1
kind: Route
metadata:
 labels:
   app: httpd
 name: httpd-front
 namespace: webserver
spec:
 host: httpd-front-webserver.apps.ipi-default.testipi.com
 port:
   targetPort: 8080-tcp
 to:
   kind: Service
   name: httpd-front

Root Cause

  • When service has multiple ports configuration, the targetPort specification is required in the route configuration for the router to map the endpoint port in the service.
  • If the route is created using a yaml file and the target port is not identified in the route definition for a service with multiple ports, the HAProxy server will configure the backend server with each port service configuration as an endpoint causing the error message in the router log.
  • If the service with multiple ports is exposed by oc cli without port specification, the route will be configured with the first target port of the service as target port for the route to configure the backend server.

Diagnostic Steps

  • Errors such below can be found in the router log:

    [ALERT] 153/5425 (947) : parsing [/var/lib/haproxy/conf/haproxy.config:1964] : backend 'be_edge_http:httpd:httpd-multi-bad', another server named 'httpd:httpd-multi-bad_httpd-2-hvm6n' was already defined at line 1963, please use distinct names.

  • As no targetPort is identified, the HAProxy server configure the backend server with the different services target ports as endpoints in the haproxy.config file:

    backend be_edge_http:httpd:httpd-multi-bad
mode http
option redispatch
option forwardfor
balance leastconn

timeout check 5000ms
http-request add-header X-Forwarded-Host %[req.hdr(host)]
http-request add-header X-Forwarded-Port %[dst_port]
http-request add-header X-Forwarded-Proto http if !{ ssl_fc }
http-request add-header X-Forwarded-Proto https if { ssl_fc }
http-request add-header X-Forwarded-Proto-Version h2 if { ssl_fc_alpn -i h2 }
http-request add-header Forwarded for=%[src];host=%[req.hdr(host)];proto=%[req.hdr(X-Forwarded-Proto)]
cookie c0fbca3e63e2574366f4985b49f32725 insert indirect nocache httponly secure attr SameSite=None
server pod:httpd-dc-2-hvm6n:httpd-dc:8080-tcp:10.129.2.123:8080 10.129.2.123:8080 cookie fe81a53c1f56c61492c3f32dffd548a3 weight 256 check inter 5000ms
server pod:httpd-dc-2-hvm6n:httpd-dc:18080-tcp:10.129.2.123:18080 10.129.2.123:18080 cookie 8e9872d5ee84c874603316e14eb3d25c weight 256 check inter 5000ms
server pod:httpd-dc-2-hvm6n:httpd-dc:mon:10.129.2.123:18081 10.129.2.123:18081 cookie 1e25ff6d0de6377fa9cb431de483a93f weight 256 check inter 5000ms

  • Route has no port identification

    $ oc get routes
NAME         HOST/PORT                                           PATH   SERVICES     PORT        TERMINATION   WILDCARD
httpd        httpd-webserver.apps.ipi-default.testipi.com               httpd        8080-tcp                  None
httpd-bad    httpd-bad-webserver.apps.ipi-default.testipi.com           httpd        <all>                     None
httpd-good   httpd-good-webserver.apps.ipi-default.testipi.com          httpd        18080-tcp                 None

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