Is it possible to have a fallback service for Kubernetes ingresses in the event that none of the normal pods are live/ready? In other words, how would you go about presenting a friendly "website down" page to visitors if all pods crashed or went down somehow?
Right now, a page appears that says "default backend - 404" if that happens.
Here's what we tried, to no avail:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: example-ingress
spec:
backend:
serviceName: website-down-service
servicePort: 80
rules:
- host: example.com
http:
paths:
- path: /
backend:
serviceName: example-service
servicePort: 80
For reference, we're testing locally with Minikube and deploying to the cloud on Google's Container Engine.
If using Nginx then default backend annotation should do the trick, sample:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-name
namespace: your-namespace
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/default-backend: fallback-backend
spec:
<your spec here>
For the Nginx Ingress Controller there is a flag --default-backend-service, which currently points to the service showing the "default backend - 404" message. Just replace it with the service you want. See https://github.com/kubernetes/ingress/tree/master/controllers/nginx#command-line-arguments
If you're using another Ingress Controller, I expect it to have a similar option.
Related
I am trying to deploy Jaeger all-in-one image in a kubernetes cluster.
Jaeger is not in the root of the url, meaning it's accessible through https://somedomain.com/xyz/jaeger
I have an ingress rule which seems to be pointing correctly to a Service which is also referencing fine the pod in a deployment (I can see all this in Rancher UI).
But somehow when I try to access, nginx is throwing a 502 Bad Gateway error.
This is how the ingress rule looks like
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: my-ingress
namespace: my-namespace
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
rules:
- host: somedomain.com
http:
# Jaeger
- path: /xyz/jaeger(/|$)(.*)
pathType: Prefix
backend:
service:
name: jaeger
port:
number: 16868
Then in the pod definition I tried using the QUERY_BASE_PATH env var setting it to /xyz/jaeger but that made no difference at all.
The problem was an incorrect port being specified.
16868 instead of 16686
I am trying to setup Prometheus in k8 cluster, able to run using helm. Accessing dashboard when i expose prometheus-server as LoadBalancer service using external ip.
Same does not work when I try to configure this service as ClusterIP and making it as backend using ingress controller. Receiving 404 error, any thoughts on how to troubleshoot this?
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ops-ingress
annotations:
#nginx.org/server-snippet: "proxy_ssl_verify off;"
nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
rules:
- http:
paths:
- path: /prometheus(/|$)(.*)
backend:
serviceName: prometheus-server
servicePort: 80
with above ingress definition in place, url “http://<>/prometheus/ getting redirected to http://<>/graph/ and then 404 error page getting rendered. When url adjusted to http://<>/prometheus/graph some of webcontrols gets rendered with lots of errors on browser console.
Prometheus might be expecting to have control over the root path (/).
Please change the Ingress to prometheus.example.com and it should work fine. (Changing it to a subdomain)
Please change your Ingress configuration file, add host field:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ops-ingress
annotations:
#nginx.org/server-snippet: "proxy_ssl_verify off;"
nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
rules:
- host: prometheus.example.com
http:
paths:
- path: /prometheus(/|$)(.*)
backend:
serviceName: prometheus-server
servicePort: 80
then apply changes executing command:
$ kubectl aply -f your_ingress_congifguration_file.yaml
The host header field in a request provides the host and port
information from the target URI, enabling the origin server to
distinguish among resources while servicing requests for multiple
host names on a single IP address.
Please take a look here: hosts-header.
Ingress definition: ingress.
Useful information: helm-prometheus.
Useful documentation: ingress-path-matching.
My app does not work when I use a path other than / in the ingress rule. The app works when I access the application using http://gv.cloud.test.com:nodeport outside kubernetes cluster however does not work with http://gv.cloud.test.com/mytestapp. Can someone help me? The web app is using / as the base_href path in angular.
I am using traefik as the ingress controller. I have tried all the available traefik rule types:
PathPrefixStrip
PathPrefix
etc
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: traefik
traefik.ingress.kubernetes.io/rule-type: PathPrefixStrip
labels:
app: my-testapp
env: dev
name: my-testapp-dev-ingress
namespace: jenkins
spec:
rules:
- host: gv.cloud.test.com
http:
paths:
- backend:
serviceName: my-testapp-service
servicePort: 8090
path: /mytestapp
I need to set a custom error in traefik ingress on kubernetes so that when there is no endpoint or when the status is "404", or "[500-600]" it redirects to another error service or another custom error message I used the annotation as it's in the documentation in the ingress file as this (Note: this a helm template output of passing the annotation as a yaml in the values.yaml file)
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: frontend
namespace: "default"
annotations:
external-dns.alpha.kubernetes.io/target: "domain.com"
kubernetes.io/ingress.class: "traefik"
traefik.ingress.kubernetes.io/error-pages: "map[/:map[backend:hello-world status:[502 503]]]"
spec:
rules:
- host: frontend.domain.com
http:
paths:
- backend:
serviceName: frontend
servicePort: 3000
path: /
The answer by ldez is correct, but there are a few caveats:
First off, these annotations only work for traefik >= 1.6.x (earlier versions may support error pages, but not for the kubernetes backend)
Second, the traefik backend must be configured through kubernetes. You cannot create a backend in a config file and use it with kubernetes, at least not in traefik 1.6.x
Here's how the complete thing looks like. foo is just a name, as explained in the other answer, and can be anything:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: frontend
namespace: "default"
annotations:
external-dns.alpha.kubernetes.io/target: "domain.com"
kubernetes.io/ingress.class: "traefik"
traefik.ingress.kubernetes.io/error-pages: |-
foo:
status:
- "404"
- "500"
# See below on where "error-pages" comes from
backend: error-pages
query: "/{{status}}.html"
spec:
rules:
# This creates an ingress on an non-existing host name,
# which binds to a service. As part of this a traefik
# backend "error-pages" will be created, which is the one
# we use above
- host: error-pages
http:
paths:
- backend:
serviceName: error-pages-service
servicePort: https
- host: frontend.domain.com
http:
# The configuration for your "real" Ingress goes here
# This is the service to back the ingress defined above
# Note that you can use anything for this, including an internal app
# Also: If you use https, the cert on the other side has to be valid
---
kind: Service
apiVersion: v1
metadata:
name: error-pages-service
namespace: default
spec:
ports:
- name: https
port: 443
type: ExternalName
externalName: my-awesome-errors.mydomain.test
If you use this configuration, and your app sends a 404, then https://my-awesome-errors.mydomain.test/404.html would be shown as the error page.
The correct syntax is:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: frontend
namespace: "default"
annotations:
external-dns.alpha.kubernetes.io/target: "domain.com"
kubernetes.io/ingress.class: "traefik"
traefik.ingress.kubernetes.io/error-pages: |-
foo:
status:
- "404"
backend: bar
query: /bar
fii:
status:
- "500-600"
backend: bar
query: /bir
spec:
rules:
- host: frontend.domain.com
http:
paths:
- backend:
serviceName: frontend
servicePort: 3000
path: /
https://docs.traefik.io/v1.6/configuration/backends/kubernetes/#general-annotations
Note that, currently, the Helm Charts doesn't support this feature.
Ingress does not support that annotations that you guys are using there!
That annotations are supported with Service only, Ingress is using host section.
I can't get the nginx controller to route based on the hostname. The YAML below doesn't work - traffic goes to the default back-end / I get a 404. However, if I remove the value for host, the ingress controller successfully routes traffic to my-service. The service works successfully if I place it behind a load balancer but I want to have multiple services working for different host names so I want to use an ingress controller and use a single IP. Thoughts?
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-nginx
annotations:
ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: test1.mydomain.com
http:
paths:
- path: /
backend:
serviceName: my-service
servicePort: 80
The yaml looks slightly different than the rewrite example located here. The yaml is valid and kubectl apply or create should work but not produce the results you are expecting. Do you need the rewrite annotation or could you remove it and the back end service will respond without issue? If you don't need to rewrite anything try removing the yaml to just look like:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-nginx
spec:
rules:
- host: test1.mydomain.com
http:
paths:
- backend:
serviceName: my-service
servicePort: 80