问题
I have tried before on Openshift Origin 3.9 and Online. I have deployed a simple hello world php app on Openshift. It has a Service and a Route.
When I call the route, I am getting expected output with Hello world and the Pod IP. Let's call this pod ip as 1.1.1.1
Now i deployed same app with small text change with same label under same Service. Let's call this pod ip as 2.2.2.2
I can see both pods running in a single Service. Now when I call the route, it always shows Podip 1.1.1.1 My route never hits the second pod.
My understand is Route will call the Service and Service will load balance between available pods.
But it isn't happening. Any help is appreciated.
回答1:
The default behavior of the HAProxy router is to use a cookie to ensure "sticky" routing. This enables sessions to remain with the same pod. https://docs.openshift.com/container-platform/3.11/architecture/networking/routes.html
If you set a haproxy.router.openshift.io/disable_cookies
annotation on the route to true
it should disable this behavior.
回答2:
My understand is Route will call the Service and Service will load balance between available pods.
Typically your knowledge is right. Let's test it on your env as follows.
# oc describe svc web
Name: web
Namespace: test
Labels: app=web
Annotations: openshift.io/generated-by=OpenShiftNewApp
Selector: app=web,deploymentconfig=web
Type: ClusterIP
IP: 172.30.6.8
Port: 8080-tcp 8080/TCP
TargetPort: 8080/TCP
Endpoints: 1.1.1.1:8080,2.2.2.2:8080
Session Affinity: None
Events: <none>
Session Affinity
is None
as default value, it means round robin
for requests.
You can check the requests access as round robin
manner by looping curl
with monitoring the pods
using oc logs
or index.html
response body (if the contents is different).
while :; do curl http://172.30.177.72:8080/index.html; sleep 1; done
1.1.1.1:8080
2.2.2.2:8080
1.1.1.1:8080
2.2.2.2:8080
...
回答3:
For those who came here looking for solution; Both answers by Daein Park and Will Gordon are true.
Here is a simple catch:
If you are calling your pod externally it goes from Router to Service to Pod. If
haproxy.router.openshift.io/disable_cookies
annotation is not set totrue
on the Router, service always forwards to the same pod.Also after disabling sticky routing with annotation above you can select a loadbalancing algorithm with:
haproxy.router.openshift.io/balance
as key and one of[source,roundrobin,leastconn]
as valueIf you are calling your pod internally from another pod. It goes from Service to Pod. Service does the round robin loadbalancing just fine with default configuration.
So you should:
- Add the said annotation to your router if you want your service exposed by a router.
- Do nothing if you want your service to be accessed only internally
(Tested on Openshift 4.2.28)
来源:https://stackoverflow.com/questions/54553179/openshift-route-is-not-load-balancing-from-service-pods