externalip | get your external ip in Node.js | Runtime Evironment library

That's totally possible, I have done it in the past as well with OpenShift 3.10. The approach to use externalIPs is the right way.

As brgsousa mentioned in the comment, the solution was redeploy as DaemonSet.

Here is working yaml file:

Assuming that we are talking about Metallb using Layer2.

Addressing the following questions:

On every node I could curl ingress controller externalIP (as long as they are reachable on eth1) with host header attached and get a response from a service thats configured in coresponding ingress resource or is it valid only on node where Ingress pods are currently placed?

Is it possible to forward requests saving source ip address or attaching X-Forwarded-For header is the only option?

Dividing the solution on the premise of preserving the source IP, this question could go both ways:

To do that you would need to set the Service of type LoadBalancer of your Ingress controller to support "Local traffic policy" by setting (in your YAML manifest):

• .spec.externalTrafficPolicy: Local

This setup will be valid as long as on each Node there is replica of your Ingress controller as all of the networking coming to your controller will be contained in a single Node.

Citing the official docs:

With the Local traffic policy, kube-proxy on the node that received the traffic sends it only to the service’s pod(s) that are on the same node. There is no “horizontal” traffic flow between nodes.

Because kube-proxy doesn’t need to send traffic between cluster nodes, your pods can see the real source IP address of incoming connections.

The downside of this policy is that incoming traffic only goes to some pods in the service. Pods that aren’t on the current leader node receive no traffic, they are just there as replicas in case a failover is needed.

Metallb.universe.tf: Usage: Local traffic policy

If your use case does not require you to preserve the source IP address, you could go with the:

• .spec.externalTrafficPolicy: Cluster

This setup won't require that the replicas of your Ingress controller will be present on each Node.

Citing the official docs:

With the default Cluster traffic policy, kube-proxy on the node that received the traffic does load-balancing, and distributes the traffic to all the pods in your service.

This policy results in uniform traffic distribution across all pods in the service. However, kube-proxy will obscure the source IP address of the connection when it does load-balancing, so your pod logs will show that external traffic appears to be coming from the service’s leader node.

Metallb.universe.tf: Usage: Cluster traffic policy

Addressing the 2nd question:

What are my options to pass incoming external traffic to eth0 to an ingress listening on eth1 network?

Metallb listen by default on all interfaces, all you need to do is to specify the address pool from this eth within Metallb config.

You can find more reference on this topic by following:

• Metallb.universe.tf: FAQ: In layer 2 mode how to specify the host interface for an address pool

An example of such configuration, could be following:

Can somebody explain whay I have to use external (MetalLB, HAProxy etc) Load Balancer with Bare-metal kubernetes cluster?

You don't have to use it, it's up to you to choose if you would like to use NodePort or LoadBalancer.

Let's start with the difference between NodePort and LoadBalancer.

NodePort is the most primitive way to get external traffic directly to your service. As the name implies, it opens a specific port on all the Nodes (the VMs), and any traffic that is sent to this port is forwarded to the service.

LoadBalancer service is the standard way to expose a service to the internet. It gives you a single IP address that will forward all traffic to your service.

You can find more about that in kubernetes documentation.

As for the question you've asked in the comment, But NodePort with "externalIPs" option is doing exactly the same. I see only one tiny difference is that the IP should be owned by one of the cluster machin. So where is the profit of using a loadBalancer? let me answer that more precisely.

There are the advantages & disadvantages of ExternalIP:

The advantages of using ExternalIP is:

You have full control of the IP that you use. You can use IP that belongs to your ASN >instead of a cloud provider’s ASN.

The disadvantages of using ExternalIP is:

The simple setup that we will go thru right now is NOT highly available. That means if the node dies, the service is no longer reachable and you’ll need to manually remediate the issue.

There is some manual work that needs to be done to manage the IPs. The IPs are not dynamically provisioned for you thus it requires manual human intervention

Summarizing the pros and cons of both, we can conclude that ExternalIP is not made for a production environment, it's not highly available, if node dies the service will be no longer reachable and you will have to manually fix that.

With a LoadBalancer if node dies the service will be recreated automatically on another node. So it's dynamically provisioned and there is no need to configure it manually like with the ExternalIP.

Following container arguments work for me in our development cluster

Summarize from the comments, you just need to add a if in your code to implement the requirement. But the code you provided in comments seems not correct. As hasdrubal mentioned, continue means exist current loop and go to next iteration, so you code should be like:

Installing prometheus using the "prometheus-community/kube-prometheus-stack" helm chart could be quite an extensive topic in itself considering the fact that it has a lot of configurable options.

As the helm chart comes with "prometheus operator", we have used PodMonitor and/or ServiceMonitor CRD's as they provide far more configuration options. Here's some documentation around that.

We've installed it with setting "prometheus.prometheusSpec.serviceMonitorSelector.matchLabels" with a label value. Something like this

I don’t see any “resources:” fields (e.g. cpu, mem, etc.) assigned, and this should be the root cause. Please be aware that having resource(s) set on a HPA (Horizontal Pod Autoscaler) is a requirement, explained on official Kubernetes documentation

Please note that if some of the Pod's containers do not have the relevant resource request set, CPU utilization for the Pod will not be defined and the autoscaler will not take any action for that metric.

This can definitely cause the message unable to read all metrics on target Deployment(s).

As per RH "we can't specify externalIP parameter during the cluster installation, it should be done post-installation."