cross-region k8s inter-cluster communication in GCP - google-cloud-platform

I am looking for a way to access services/applications in a remote k8s cluster(C2) hosted in a different region(R2) from a client application in my current cluster(C1 in region R1).
Server application needs to load-balanced(fqdn preferred over IP)
Communication is through private network, no internet
I tried using an internal-LB for C2 which doesn't work and later realized it to be a regional product.
Moreover, it seems, the same constraint is true for vpc peering also.
Please suggest how to achieve this.

You can't use any internal GCP LB on a regional level. However, you may be able to use an Nginx internal ingress as it may not be limited to the same region.
Otherwise you can use Creating VPC-native clusters using Alias IPs which can allow you to call on pods directly. It will not offer built in load balancing but it is an alternative.
Finally, if you need to use the internal load balancers, you can create a VPN tunnel between the two regions and create a route that forces traffic through the gateway. Traffic coming through the tunnel will be regional to the ILB, but this config is more expensive and with more moving parts, there's a higher chance of failure

Related

Firewall issue - egress from GKE to Cloud Function HTTP Trigger

I am developing a solution where a Java application hosted on GKE wants to make an outbound HTTP call to a cloud function which is deployed under a different GCP project, where the GKE operates on a shared network of which possesses firewall rules for the CIDR ranges in that shared network.
For example - GKE cluster & Application deployed under GCP Project A, wishes to invoke a Serverless GCP Function deployed to project B.
There are a number of firewall rules configured on the shared network of which the GKE is operating upon, causing my HTTP call to time out, as the HTTP trigger URL is not mapped to an allowed CIDR range (in that shared network).
What have I tried?
I have lightly investigated one or two solutions which make use of Cloud NAT & Router to proxy the HTTP call to the Cloud Function trigger endpoint, but I am wondering if there are any other, simpler suggestions? The address range for cloud functions is massive so allowing that range is out of the question.
I was thinking about maybe deploying the cloud function into the same VPC & applying ingress restrictions to it, would that allow the HTTP trigger to exist in the allowed IP range?
Thanks in advance
Serverless VPC Access is a GCP solution specially designed to achieve what you want. The communication between the serverless environment and the VPC is done through an internal IP address, and therefore never exposed to the Internet.
For your specific infrastructure, you would need to follow the guide Connecting to a Shared VPC network.

ECS Fargate cross microservice communication options

I have been looking into different ways of connecting multiple miscorservices within their own services/tasks using ECS Fargate.
Normally, if all microservices are defined in the same task definition, we can just use the local ip with corresponding ports but this means we cannot scale individual microservices. From what I can tell there are two 'main' ways of enabling this communication when we break these out into multiple services:
Add a load balancer to each service and use the loadbalancers public ip as the single point of access from one service to another.
Questions I have on this is:
a. Do all the services that need to communicate need to sit in the same VPC and have the
service's incoming rules set to the security group of the load balancer?
b. Say we have now provisioned the entire set up and need to set one of the loadbalancer public DNS's in one microservices code base, whats the best way of attaining this, im guessing some sort of terraform script that 'assumes' the public DNS that will be added to it?
Making use of AWS Service Discovery, meaning we can query service to service with a simple built up identifier.
Question I have for this is:
a. Can we still attach load balancers to the services and STILL use service discovery? Or
does service discovery have an under the hood load balancer already configured?
Many thanks in advance for any help!
1.a All services in the same VPC and their security groups (SGs)
I assume that you are talking about case where each service will have its own load balancer (LB). Since the LBs are public, they can be in any VPC, region or account.
SGs are generally setup so that incoming rules to services allow only connections from the SG of the LB.
1.b DNS
Each task can have environmental variables. This is a good way to pass the DNS values. If you are taking about terraform (TF), then TF would provision the LBs and then create the tasks and set the env variables with DNS values of the LBs. Thus, you would know the DNS of LBs as they would have been created before your services.
2.a Service discovery (SD)
SD is only for private communication between services. No internet is involved, so everything must be in same VPC or peered-VPCs. So its basically oposite of the first solution with LBs.
I think you should be able to also use public LB along with SD.
SD does not use a LB. Instead when you query a DNS of a service through SD you will get private IP addresses of the tasks in random order. So the random order approximates load balancing of connections between tasks in a service.

How to make GKE clusters communicate using private IPs or networks?

Is there any way to make GKE clusters (in the same network) talk to each other using internal IP addresses?
I know GKE internal load balancers can handle traffic only from the same network and the same region. And I find this implementation very strange.
I understand pod IPs are routable but they are not static and can change anytime. Also, I know there is loadBalancerSourceRanges configuration option in external load balancers using which I can allow only the subnets I want but what if I want to keep every communication using internal and not using a public IP?
Is there any way to achieve what I am trying? Like configuring the Firewall Rules or anything else? or "Global routing mode" while creating the VPC network or anything?
If you have 2 clusters in 2 different regions and you want them to communicate using internal IPs, your best option is to use nodePort service in the clusters to expose your pods and then configure a VM instance to act as a proxy for each cluster.
This will have the same effect as using the LoadBalancer service as an internal Load Balancer but it has the benefit that it will work across multiple regions. It also allows the same Load Balancer to handle requests for all your services.
The one thing you need to be careful of is overloading the proxy instance. Depending on the number of requests, you may need to configure multiple proxy instances for the cluster, each one only handline a handful of services.
Thanks to Global Access, adding networking.gke.io/internal-load-balancer-allow-global-access: "true" to annotation will allow you to communicate across regions.
"Global access is available in Beta on GKE clusters 1.16+ and GA on 1.17.9-gke.600+."
https://cloud.google.com/kubernetes-engine/docs/how-to/internal-load-balancing#global_access

How to expose APIs endpoints from private AWS ALB

We are having several microservices on AWS ECS. We have single ALB which has different target group for different microservices. We want to expose some endpoints externally while some endpoints just for internal communication.
The problem is that if we put our load balancer in public VPC than it means that we are exposing all register endpoints externally. If we move load balancer to private VPC, we have to use some sort of proxy in public VPC, which required additional infra/cost and custom implementation of all security concerns like D-DOS etc.
What possible approaches we can have or does AWS provide some sort of out of the box solution for this ?
I would strongly recommend running 2 albs for this. Sure, it will cost you more (not double because the traffic costs won't be doubled), but it's much more straight forward to have an internal load balancer and an external load balancer. Work hours cost money too! Running 2 albs will be the least admin and probably the cheapest overall.
Checkout WAF. It stands for web application firewall and is available as AWS service. Follow these steps as guidance:
Create a WAF ACL.
Add "String and regex matching" condition for your private endpoints.
Add "IP addresses" condition for your IP list/range that are allowed to access private endpoints.
Create a rule in your ACL to Allow access if both conditions above are met.
Assign ALB to your WAF ACL.
UPDATE:
In this case you have to use external facing ALB in a public subnet as mentioned by Dan Farrell in comment below.
I would suggest doing it like this:
one internal ALB
one target group per microservice, as limited by ECS.
one Network load balancer(NLB), with one ip based target group.
The Ip based target group will have the internal ALB ip addresses,as the private ip addresses for ALB are not static, you will need to setup cloudwatch cron rule with this lambda function(forked from aws documentation and modified to work on public endpoints as well):
https://github.com/talal-shobaita/populate-nlb-tg-withalb/
Both ALB and NLB are scalable and protected from DDOS by AWS, AWS WAF is another great tool that can be attached directly to your ALB listener for extended protection.
Alternatively, you can wait for AWS to support multiple target group registration per service, it is already in their roadmap:
https://github.com/aws/containers-roadmap/issues/104
This how we eventually solved.
Two LB one in private and one in public subnet.
Some APIs meant to be public, so directly exposed through public LB.
For some private APIs endpoints need to be exposed, added a proxy in public LB and routed those particular paths from public LB to private LB through this proxy.
These days API Gateway is the best way to do this. You can have your API serve a number of different endpoints while serving only the public ones via API Gateway and proxying back to the API.
I don't see it mentioned yet so I'll note that we use a CloudMap for internal routing and an ALB for "external" (in our case simply intra/inter-VPC) communication. I didn't read in depth, but I think this article describes it.
AWS Cloud Map is a managed solution that lets you map logical names to the components/resources for an application. It allows applications to discover the resources using one of the AWS SDKs, RESTful API calls, or DNS queries. AWS Cloud Map serves registered resources, which can be Amazon DynamoDB tables, Amazon Simple Queue Service (SQS) queues, any higher-level application services that are built using EC2 instances or ECS tasks, or using a serverless stack.
...
Amazon ECS is tightly integrated with AWS Cloud Map to enable service discovery for compute workloads running in ECS. When you enable service discovery for ECS services, it automatically keeps track of all task instances in AWS Cloud Map.
You want to look at AWS Security Groups.
A security group acts as a virtual firewall for your instance to control inbound and outbound traffic.
For each security group, you add rules that control the inbound traffic to instances, and a separate set of rules that control the outbound traffic.
Even more specific to your use-case though might be their doc on ELB Security Groups. These are, as you may expect, security groups that are applied at the ELB level rather than the Instance level.
Using security groups, you can specify who has access to which endpoints.

Amazon Elastic Beanstalk internal and internet access

We’re trying to create a setup of multiple APIs via the Amazon AWS Elastic Beanstalk (AEB) component. The reason we have chosen AEB is because it provides seamless deployment and scaling for the applications we deploy, without the need to manually create Load Balancers (LB) and scaling rules. We would very much like to keep it this way as we are planning on launching a (large) number of applications and APIs.
However, we’re facing a number of challenges with AEB.
First and foremost, some of the API’s need to communicate internally, and low latency is a core requirement for us. In order to utilize internal network communication in AEB we have been “forced” to:
Allocate a VPC in Amazon
Deploy each application to this VPC - each behind their own internal LB
Now, when using the Elastic beanstalk URLs the APIs are able to resolve the internal IP of the LB of another API and thus the latency is eliminated and all is good - the APIs can communicate with one another.
However, this spawns another issue for us:
Some of these “internally” allocated APIs (remember, they’re behind an internal LB in a VPC) must also be accessible from the internet.
We still haven’t found a way to make the internal LBs internet accessible (while keeping their ability to also act as internal LB), so any help on this matter is greatly appreciated.
Each application should be on a subnet within VPC
Update ACL and ELB Security Group to let external access
AWS Elastic Load Balancing Inside of a Virtual Private Cloud
Also, this question on SO contains relevant information: Amazon ELB in VPC