Configuring OpenShift with Multiple Sharded Routers

January 29, 2017

I needed to host a service that would be consumed by a closed client that insists on speaking HTTPS on port 50,000. To solve this, I added a 2nd router deployment and used the OpenShift router sharding feature to selectively enable routes on the 2nd router by way of selectors.

To summarize:

Existing HA router:

HTTP 80
HTTPS 443
Haproxy Stats 1,936

Added HA router:

HTTP 49,999
HTTPS 50,000
Haproxy Stats 51,936

How To

Open infra node firewalls

Open firewall on infra nodes where router will run to allow new http and https port

 iptables -A OS_FIREWALL_ALLOW -m tcp -p tcp --dport 49999 -j ACCEPT
 iptables -A OS_FIREWALL_ALLOW -m tcp -p tcp --dport 50000 -j ACCEPT

This can also be done with Ansible and the os_firewall role in your playbook. (untested)

- hosts: infra-nodes

  vars:
    os_firewall_use_firewalld: False
    os_firewall_allow:
      - service: teradici-http
        port: 49999/tcp
      - service: teradici-https
        port: 50000/tcp

  roles:
    - os_firewall

Create a router

Create a router called ha-router-teradici with oa adm router or oadm router on these ports and also make sure the stats port does not clash with existing router on port 1936

[root@ose-test-master-01 ~]# oc get nodes --show-labels
NAME                           STATUS    AGE       LABELS
ose-test-master-01.example.com   Ready     180d      kubernetes.io/hostname=ose-test-master-01.example.com,region=master,zone=rhev
ose-test-master-02.example.com   Ready     180d      kubernetes.io/hostname=ose-test-master-02.example.com,region=master,zone=rhev
ose-test-node-01.example.com     Ready     180d      ha-router=primary,kubernetes.io/hostname=ose-test-node-01.example.com,region=infra,zone=rhev
ose-test-node-02.example.com     Ready     180d      ha-router=primary,kubernetes.io/hostname=ose-test-node-02.example.com,region=infra,zone=rhev
ose-test-node-03.example.com     Ready     180d      kubernetes.io/hostname=ose-test-node-03.example.com,region=primary,zone=rhev
ose-test-node-04.example.com     Ready     180d      kubernetes.io/hostname=ose-test-node-04.example.com,region=primary,zone=rhev

[root@ose-test-master-01 ~]#  oadm router ha-router-teradici \
    --ports='49999:49999,50000:50000' \
    --stats-port=51936 \
    --replicas=2 \
    --selector="ha-router=primary" \
    --selector="region=infra" \
    --labels="ha-router=teradici" \
    --default-cert=201602_router_wildcard.os.example.com.pem \
    --service-account=router

GOOD: I see that the ports are set properly in the haproxy.config and the service objects

OpenShift High Availability - Routing

March 1, 2016

Highly availabile containers in OpenShift are baked into the cake thanks to replication controllers and service load balancing, but there are plenty of other single points of failure. Here is how to eliminate many of those.

Single Points of Failure

The components of OpenShift include:

Master controller manager server and API endpoint
Etcd configuration and state storage
Docker Registry
Router haproxy

This post is mostly about adding high availability to the routing layer.