I have a query which is basically a clarification regarding Routes in OpenShift Origin.
I managed to setup OpenShift Origin version 1.4.0-rc1 on a CentOS hosted in local VMWare installation. Am also able to pull and setup image for nginx and pod status shows Running. Able to access nginx on the service endpoint also. Now as per documentations if I want to access this nginx instance outside the hosted system I need to create a Route, which I also did.
Confusion is on the Create Route screen from OpenShift Web Console it generates a hostname or allows to enter a hostname. Both of the option i tried, generated hostname seems to be a a long subdomain kind of hostname and it doesn't work. What I mean is I'm not able to access this hostname from anywhere in the network including the hosting OS as well.
To summarize, service endpoints which looks like 172.x.x.x is working on the local machine which is hosting OpenShift. But the generated/entered hostname for the route doesn't work from anywhere.
Please clarify the idea behind this route concept and how could one access a service from outside the host machine (Part of same network)
As stated in documentation:
An OpenShift Origin route exposes a service at a host name, like
www.example.com, so that external clients can reach it by name. DNS
resolution for a host name is handled separately from routing; your
administrator may have configured a cloud domain that will always
correctly resolve to the OpenShift Origin router, or if using an
unrelated host name you may need to modify its DNS records
independently to resolve to the router.
It is important to notice the difference between "route" and "router". The Opensfhit router (that is mentioned above)listens to all requests to Openshift deployed applications, and has to be previoulsy deployed, in order for routes to work.
https://docs.openshift.org/latest/architecture/core_concepts/routes.html
So once you have the router deployed and working, all routes that you create in openshift should resolve where that Openshift router is listening. For example, configuring your DNS with a wildcard (this is dnsmaq wildcard example):
address=/.yourdomain.com/107.117.239.50
This way all your "routes" to services should be like this:
service1.yourdomain.com
service2.yourdomain.com
...
Hope this helps
Related
I'm not able to get a custom domain record working with an openshift cluster. I've read tons of articles, StackOverflow posts, and this youtube video https://www.youtube.com/watch?v=Y7syr9d5yrg. All seem to "almost" be usefull for me, but there is always something missing and I'm not able to get this working by myself.
The scenario is as follows. I've got an openshift cluster deployed on an IBM Cloud account. I've registered myinnovx.com. I want to use it with an openshift app. Cluster details:
oc v3.11.0+0cbc58b
kubernetes v1.11.0+d4cacc0
openshift v3.11.146
kubernetes v1.11.0+d4cacc0
I've got an application deployed with a blue/green strategy. In the following screenshot, you can see the routes I've available.
mobile-blue: I created this one manually pointing to my custom domain mobileoffice.myinnovx.com
mobile-office: Created with oc expose service mobile-office --name=mobile-blue to use external access.
mobile-green: Openshift automatically generated a route for the green app version. (Source2Image deployment)
mobile-blue: Openshift automatically generated a route for the blue app version. (Source2Image deployment)
I've set up a two CNAME record on my DNS edit page as follows:
In several blogs/articles, I've found that I'm supposed to point my wildcard record to the router route canonical name. But I don't have any route canonical name in my cluster. I don't even have an Ingress route configured.
I'm at a loss here as to what I'm missing. Any help is greatly appreciated.
This is the response I get testing my DNS:
This is a current export of my DNS:
$ORIGIN myinnovx.com.
$TTL 86400
# IN SOA ns1.softlayer.com. msalimbe.ar.ibm.com. (
2019102317 ; Serial
7200 ; Refresh
600 ; Retry
1728000 ; Expire
3600) ; Minimum
# 86400 IN NS ns1.softlayer.com.
# 86400 IN NS ns2.softlayer.com.
*.myinnovx.com 900 IN CNAME .mycluster-342148-26562a7d6831df3dfa02975385757d2d-0001.us-south.containers.appdomain.cloud.
mobileoffice 900 IN CNAME mobile-office-mobile-office.mycluster-342148-26562a7d6831df3dfa02975385757d2d-0001.us-south.containers.appdomain.cloud
mobile-test.myinnovx.com 900 IN A 169.63.244.76
I think you almost got it, Matias.
The FQDN - mobile-office-mobile-office.mycluster-342148-26562a7d6831df3dfa02975385757d2d-0001.us-south.containers.appdomain.cloud - resolves for me to an IP that is part of SOFTLAYER-RIPE-4-30-31 and is accessible from the Internet. So, it should be possible to configure what you want.
That snapshot in your question of the DNS records isn't displaying the entries in full but what might be missing is a dot . at the end of both the "Host/Service" and "Value/Target". Something like this:
mobileoffice.myinnovx.com. CNAME 900 (15min) mobile-office-mobile-office.mycluster-342148-26562a7d6831df3dfa02975385757d2d-0001.us-south.containers.appdomain.cloud.
Most of what I'm about to say only applies to OpenShift 3.x. In OpenShift 4.x things are sufficiently different that most of the below doesn't quite apply.
By default OpenShift 3.11 exposes applications via Red Hat's custom HAProxy Ingress Controller (colloquially known as the "Router"). The typical design in a OpenShft 3.x cluster is to designate particular cluster hosts for running cluster infrastructure workloads like the HAProxy router and the internal OpenShift registry (usually using the node-role.kubernetes.io/infra=true node labels).
For convenience purposes so admins don't have to manually create a DNS record for each exposed OpenShift application, there is a wildcard DNS entry that points to the load balancer associated with the HAProxy Router. The DNS name of this is configured in the openshift_master_default_subdomain of the ansible inventory file used to do your cluster installation.
The structure of this record is generally something like *.apps.<cluster name>.<dns subdomain>, but it can be anything you like.
If you want to have a prettier DNS name for your applications you can do a couple things.
The first is to create a DNS entry myapp.example.com pointing to your load balancer and have your load balancer configured to forward those requests to the cluster hosts where the HAProxy Router is running on port 80/443. You can then configure your application's Route object to use hostname myapp.example.com instead of the default <app name>-<project name>.apps.<cluster name>.<dns subdomain>.
Another method would be to do what your suggesting and let the application use the default wildcard route name, but create a DNS CNAME pointing to the original wildcard route name. For example if my openshift_master_default_subdomain is apps.openshift-dev.example.com and my application route is myapp-myproject.apps.openshift-dev.example.com then I could create a CNAME DNS record myapp.example.com pointing to myapp-myproject.apps.openshift-dev.example.com.
The key thing that makes either of the above work is that the HAProxy router doesn't care what the hostname of the request is. All its going to do is match the Host header (SNI must be set in the case of TLS requests and the HAProxy router configured for pass through) of the incoming request against all of Route objects in the cluster and see if any of them match. So if your DNS/Load Balancer configuration is setup to bring requests to the HAProxy Router and the Host header matches a Route, that request will get forwarded to the appropriate OpenShift service.
In your case I don't think you have the CNAME pointed at the right place. You need to point your CNAME at the wildcard hostname your application Route is using.
Also, please note the instructions for custom DNS setup for a route on OpenShift v4 are a bit different and are not correctly displayed in the web console:
apps.<clustername>.<clusterid>.<shard>.openshiftapps.com will not resolve to anything. *.apps.<clustername>.<clusterid>.<shard>.openshiftapps.com is the wildcard entry, so you need something prepending that.
To align with the way it was on v3 we usually chose the arbitrary string elb, e.g. - elb.apps.<clustername>.<clusterid>.<shard>.openshiftapps.com. That will hit the routers.
Here is the related BZ - https://bugzilla.redhat.com/show_bug.cgi?id=1925132
I built simple cluster in GKE with two services using this tutorial
https://cloud.google.com/kubernetes-engine/docs/tutorials/hello-app
After finishing that I'm able to access my service using external IP address. So I bought domain for using this IP address. After setup A record in DNS settings to that IP address, domain doesn't work, it still loads and then show ERR_CONNECTION_TIMED_OUT. Do I need to do something in google console, or how I can make this IP public and accessed through domain?
Please refer to official documentation, which describes steps you need to take to configure domain names with static IP.
There are steps that you need to cover:
Go to NETWORKING section at GCP console, than VPC Network -> External IP addresses to ensure that you are running static IP address, not ephemeral one.
Go to Network services -> Cloud DNS. You need to create DNS zone, where at DNS name line you have to wright your domain name. After creation you will see Add record set, where you need to paste your external IP address.
There is also a good tutorial at YouTube with setting up custom domain on GCP. Let me know if it works for you.
I have an application running on my own server with kubernetes. This application is supposed to work as a gateway and has a LoadBalancer service, which is exposing it to "the world". Now I'd like to connect this application with other applications running within the very same kubernetes cluster, so they can exchange HTTP requests with each other.
So let's say that my Gateway app is running on the port 9000, the app which I'd like to call runs on 9001. When I make curl my_cluster_ip:9001 it gives me a response. Nevertheless I never know, what the Cluster IP will be, so I can't implement this to my gateway app.
Use case is typing to the web browser url_of_my_server:9000 -> this will call the gateway -> it sends HTTP Request to the other app running in the cluster on the port 9001 -> response back to the gateway -> response back to the user.
Where the magic has to happen and how to easily make these two apps to talk with each other, while only one will be exposed to "the world" and the other one will be accessible only from within the cluster?
You can expose your app on port 9001 as a service (lets say myservice).
When you do that myservice.<namespace>.svc.cluster.local will resolve to IP addres of your app. More Info on DNS here : https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/
And then you can access your app within Kubernetes cluster as:
http://myservice.<namespace>.svc.cluster.local:9001
You have a couple of options for internal service discovery:
You can use the cluster-internal DNS service to find the other application, as detailed in the answer by bits.
if both the proxy and the app runs in the same namespace, there are environment variables that expose the IP and ports. This may mean you have to restart the proxy if you remove/readd the other application, as the ports may change.
you can run both apps as two different containers in the same pod; this will ensure they get scheduled on the same host, which allows you to communicate on the same host.
Also note that support for your HTTP proxy setup already exist in Kubernetes; take a look at Ingress and Ingress Controllers.
I created a VM instance and deployed my application. I can access the application through the given external IP address, but I want to access it with some domain, just like openshift provides a domain AAA.rhcloud.com, which we can use the access the projects from the VM.
Is it possible to do it easily without normal DNS and CNAME route?
Thanks,
Manish
Most IP addresses have a DNS address than you can find out with reverse DNS:
$ dig +short -x 104.197.1.2
2.1.197.104.bc.googleusercontent.com.
As you can see on GCE you can reverse the IP address and append bc.googleusercontent.com. Of course this is no easier to remember than the IP address itself.
Between GCE instances in the same project, you can also use INSTANCE_NAME.c.PROJECT_ID.internal, but this won't work from outside GCE.
With a standard Kubernetes deployment on Google Container Engine, to include services configured with the Kubernetes load balancer settings which creates network load balancers, is it possible to access the user's (or referring) IP address in an application? In the case of PHP, checking common headers in the $_SERVER superglobal only results in the server and internal network addresses being available.
Not yet. Services go through kube_proxy, which answers the client connection and proxies through to the backend (your PHP server). The address that you'd see would be the IP of whichever kube-proxy the connection went through.
Work has been done, and a tracking issue is still open to switch over to an iptables-only proxy. That would allow your PHP server to get the actual client IP.