Is there a way to keep the same external IP that current load balancer has even when I make a new deployment?
When I delete the deployment connected to the load balancer, load balancer still stays so is it possible to connect a new deployment to that existing load balancer?
yes, you can pass the externalIP in the service object's yaml file.
Try following this -
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
selector:
app: MyApp
ports:
- protocol: TCP
port: 80
targetPort: 9376
loadBalancerIP: 78.11.24.19
type: LoadBalancer
Please refer to https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer for more info on this
Related
I am able to configure Nginx for NodePort and access it, but when I configure Load Balancer and Target Group for Nginx I am not able to access. I think I am doing something wrong and I cannot troubleshoot it as I am quite new to Kubernetes.
nginx-service.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx-service
labels:
app: nginx
svc: test-nginx
spec:
type: LoadBalancer
selector:
app: nginx
ports:
- protocol: TCP
port: 8080
targetPort: 80
nodePort: 30000
Load Balancer and Target group configuration
You need to use ingress controller to do the same thing.
That will automatically create the load balancer and target group from the file itself.
You can watch the videos and tutorials for the same.
Your image attachment indicated that your ALB was attached with the VPC default security group. Your EC2 instance security group will need to have inbound rule for the default security group for connectivity. You can automate this process by using the AWS LB Controller.
In Kubernetes, a Service is linked to a Deployment with the selector property of the Service and the label property of the Deployment.
Then, can a Service be linked to Deployments or pods with different images?
A Service can select all the pods whose labels are matched with service selector. It does not matter what images those pods have.
As far the k8s doc about service:
An abstract way to expose an application running on a set of Pods as a network service.
With Kubernetes you don't need to modify your application to use an unfamiliar service discovery mechanism. Kubernetes gives Pods their own IP addresses and a single DNS name for a set of Pods, and can load-balance across them.
So as far your question, the answer is yes.
For example, let's say about this service yaml, for this service it will select all the pods that have app: MyApp label, it does not matter what are in those pods.
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
selector:
app: MyApp
ports:
- protocol: TCP
port: 80
targetPort: 9376
You can read more about Service then you will clear about it.
In kubernetes a service is not linked to Deployment. It is bound to all the pods using a 'selector'.
see below an example:
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
selector:
app: my-app
ports:
- protocol: TCP
port: 80
targetPort: 9376
In this case, the below YAML creates a new Service object named "my-service", which targets TCP port 9376 on any Pod with the "app=my-app" label
I have a DaemonSet with a service pointing to it.
When a pod will access the ClusterIP of the my service, will it get the local pod running on the same node or any pod in the service?
Is there any way to achieve this? My understanding is that it would be the same thing than externaltrafficpolicy: local but for internal traffic.
By default, traffic sent to a ClusterIP or NodePort Service may be routed to any backend address for the Service. Since Kubernetes 1.7 it has been possible to route "external" traffic to the Pods running on the Node that received the traffic, but this is not supported for ClusterIP Services, and more complex topologies — such as routing zonally — have not been possible. The Service Topology feature resolves this by allowing the Service creator to define a policy for routing traffic based upon the Node labels for the originating and destination Nodes.
You need to use: Service topology
An example service which prefers local pods:
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
selector:
app: my-app
ports:
- protocol: TCP
port: 80
targetPort: 9376
topologyKeys:
- "kubernetes.io/hostname"
- "*"
UPD 1:
There is another option to make sure, that requests sent to a port of some particular node will be handled on the same node - it's hostPort.
An example:
kind: Pod
apiVersion: v1
metadata:
name: test-api
labels:
app: test-api
spec:
containers:
- name: testapicontainer
image: myprivaterepo/testapi:latest
ports:
- name: web
hostPort: 55555
containerPort: 80
protocol: TCP
The above pod will expose container port 80 on a hostPort: 55555 - if you have DaemonSet for those pods - then you can be sure, that they will be run on each node and each request will be handled on the node which received it.
But, please be careful using it and read this: Configuration Best Practices
I have many tenants running on one Kubernetes cluster (on AWS), where every tenant has one Pod that exposes one TCP port (not HTTP) and one UDP port.
I don't need load balancing capabilities.
The approach should expose an IP address that is externally available with a dedicated port for each tenant
I don't want to expose the nodes directly to the internet
I have the following service so far:
apiVersion: v1
kind: Service
metadata:
name: my-service
labels:
app: my-app
spec:
type: NodePort
ports:
- port: 8111
targetPort: 8111
protocol: UDP
name: my-udp
- port: 8222
targetPort: 8222
protocol: TCP
name: my-tcp
selector:
app: my-app
What is the way to go?
Deploy a NGINX ingress controller on your AWS cluster
Change your service my-service type from NodePort to ClusterIP
Edit the configMap tcp-services in the ingress-nginx namespace adding :
data:
"8222": your-namespace/my-service:8222
Same for configMap udp-services :
data:
"8111": your-namespace/my-service:8111
Now, you can access your application externally using the nginx-controller IP <ip:8222> (TCP) and <ip:8111> (UDP)
The description provided by #ffledgling is what you need.
But I have to mention that if you want to expose ports, you have to use a load balancer or expose nodes to the Internet. For example, you can expose a node to the Internet and allow access only to some necessary ports.
I'm trying to expose my Deployment to a port which I can access through my local computer via Minikube.
I have tried two YAML configurations (one a load balancer, one just a service exposing a port).
I: http://pastebin.com/gL5ZBZg7
apiVersion: v1
kind: Service
metadata:
name: bot
labels:
app: bot
spec:
type: LoadBalancer
ports:
- port: 8000
targetPort: 8000
protocol: TCP
selector:
app: bot
II: http://pastebin.com/sSuyhzC5
apiVersion: v1
kind: Service
metadata:
name: bot
labels:
app: bot
spec:
ports:
- port: 8000
targetPort: 8000
protocol: TCP
selector:
app: bot
The deployment and the docker container image both expose port 8000, and the Pod is tagged with app:bot.
The first results in a service with a port which never finishes, and the external IP never gets assigned.
The second results in a port of bot:8000 TCP, bot:0 TCP in my dashboard and when I try "minikube service bot" nothing happens. The same happens if I type in "kubectl expose service bot".
I am on Mac OS X.
How can I set this up properly?
The LoadBalancer service is meant for Cloud providers and not really relevant for minikube.
From the documentation:
On cloud providers which support external load balancers, setting the type field to "LoadBalancer" will provision a load balancer for your Service.
Using a Service of type NodePort (see documentation) as mentioned in the Networking part of the minikube documentation is the intended way of exposing services on minikube.
So your configuration should look like this:
apiVersion: v1
kind: Service
metadata:
name: bot
labels:
app: bot
spec:
type: NodePort
ports:
- port: 8000
targetPort: 8000
nodePort: 30356
protocol: TCP
selector:
app: bot
And access your application through:
> IP=$(minikube ip)
> curl "http://$IP:30356"
Hope that helps.
Minikube now has the service command to access a service.
Use kubectl service <myservice>.
That will give you a URL which you can use to talk to the service.