Initial open source commit

Author: kuntalkumarbasu

.gitignore

@@ -0,0 +1,23 @@
+#  Local .terraform directories
+**/.terraform/*
+
+# .tfstate files
+*.tfstate
+*.tfstate.*
+
+# .tfvars files
+*.tfvars
+
+*.sw*
+
+# Generated files
+builds/
+
+
+#intellij idea files
+.idea/
+
+# directory with files to ignore
+ignored
+.plan
+changes.exist

.pre-commit-config.yaml

@@ -0,0 +1,5 @@
+- repo: git://github.com/antonbabenko/pre-commit-terraform
+  rev: v1.16.0
+  hooks:
+    - id: terraform_fmt
+    - id: terraform_docs

CODE_OF_CONDUCT.md

@@ -0,0 +1,76 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+ advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+ address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+ professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at rtyler@scribd.com. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see
+https://www.contributor-covenant.org/faq

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Scribd, Inc
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -1 +1,75 @@
 # terraform-aws-recycle-eks
+
+This module creates a terraform module to recycle EKS worker nodes. The high level functionalities are explained below,
+ - Use a lamdba to take an instance id as an input, to put it in standby state. Using autoscaling api to automatically add a new instance to the group while putting the old instance to standby state. The old instance will get into "Standby" state only when the new instance is in fully "Inservice" state
+ - Taint this "Standby" node in EKS using K8S API in Lambda to prevent new pods from getting scheduled into this node
+ - Periodically use K8S API check for status of “stateful” pods on that node based on the label selector provided. Another Lambda will do that
+ - Once all stateful pods have completed on the node, use K8S API in another Lambda to drain the standby node
+ - Once the number of running pod reached 0, shut down that standby instance using AWS SDK.
+ - We are not termnating the node, only shutting it down, hust in case. In future releases, we will be start terminating the nodes
+
+## TODO:
+ - Check for new node in service before proceeding to put the existing node in standby state. Right now we are putting a sleep of 300 sec.
+ - Stop using anonymous role and find a way to map the role with a proper user
+ - get_bearer_token() function used in all lambda. Refactor the code to use as a Python module.
+ - Better logging and exception handling
+
+There are two main components:
+
+1. Lambdas
+2. Step Function in AWS, to chain the Lambdas and pass on the parameters form one Lamda to another Lamda
+
+
+## Usage
+
+**Set up all supported AWS / Datadog integrations**
+
+```
+module "recycl-eks-worker-npde" {
+  source = "git::git@github.com:scribd/terraform-aws-recycle-eks.git"
+  name                   = "string"
+  tags                            = {
+    Environment = "dev"
+    Terraform   = "true"
+  }
+  vpc_subnet_ids         = ["subnet-12345678", "subnet-87654321"]
+  vpc_security_group_ids = ["sg-12345678"]
+  aws_region             = "us-east-2"
+
+}
+```
+
+## Running of step function
+
+```
+Step function takes an json input 
+
+{
+    "instance_id": "i-1234567890",
+    "cluster_name": "eks-cluster-name-where-the-instance-belongs-to",
+    "label_selector":"airflow_version=1.2.3,airflow-worker" #you can put a comma separated value for labels, either key=value or only key
+}
+This label selector will be the identifier on which the step function will wait and rest all pods will be ignored.
+
+```
+
+## Development
+
+Releases are cut using [semantic-release](https://github.com/semantic-release/semantic-release).
+
+Please write commit messages following [Angular commit guidelines](https://github.com/angular/angular.js/blob/master/DEVELOPERS.md#-git-commit-guidelines)
+
+
+### Release flow
+
+Semantic-release is configured with the [default branch workflow](https://semantic-release.gitbook.io/semantic-release/usage/configuration#branches)
+
+For this project, releases will be cut from master as features and bugs are developed.
+
+
+### Maintainers
+- [Kuntal](https://github.com/kuntalkumarbasu)
+
+### Reference
+- There is an excellent module on [Gracefully drain Kubernetes pods from EKS worker nodes during autoscaling scale-in events](https://github.com/aws-samples/amazon-k8s-node-drainer). We followed some of the principles in the Lambdas.
+- [Orchestrating Amazon Kubernetes Service (EKS) from AWS Lambda](https://medium.com/@alejandro.millan.frias/managing-kubernetes-from-aws-lambda-7922c3546249) is another writeup that we referrenced while connecting to EKS from Lambda

iam.tf

@@ -0,0 +1,135 @@
+# defining aws roles and policies for a lambda function
+
+data "aws_iam_policy_document" "lambda-assume-role" {
+  statement {
+    actions = ["sts:AssumeRole"]
+
+    principals {
+      type        = "Service"
+      identifiers = ["lambda.amazonaws.com"]
+    }
+  }
+}
+resource "aws_iam_policy" "lambda_eks_policy" {
+  name        = "lambda_eks_policy"
+  path        = "/"
+  description = "Policy to provide permissions to lambda functions"
+
+  policy = <<EOF
+{
+    "Version": "2012-10-17",
+    "Statement": [
+        {
+            "Action": [
+                "sts:GetCallerIdentity",
+                "eks:DescribeCluster",
+                "autoscaling:*",
+                "ec2:TerminateInstances",
+                "ec2:StopInstances"
+            ],
+            "Effect": "Allow",
+            "Resource": "*"
+        }
+    ]
+}
+EOF
+}
+
+resource "aws_iam_role_policy_attachment" "lambda_eks_policy" {
+  role       = aws_iam_role.lambda-exec.name
+  policy_arn = aws_iam_policy.lambda_eks_policy.arn
+}
+
+resource "aws_iam_role" "lambda-exec" {
+  name                 = "${var.name}-lambda-exec-role"
+  tags                 = var.tags
+  max_session_duration = 43200
+  assume_role_policy   = data.aws_iam_policy_document.lambda-assume-role.json
+}
+
+resource "aws_iam_role_policy_attachment" "lambda-exec" {
+  role       = aws_iam_role.lambda-exec.name
+  policy_arn = "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+}
+
+resource "aws_iam_role_policy_attachment" "cluster_AmazonEKSClusterPolicy" {
+  policy_arn = "arn:aws:iam::aws:policy/AmazonEKSClusterPolicy"
+  role       = aws_iam_role.lambda-exec.name
+}
+
+resource "aws_iam_role_policy_attachment" "cluster_AmazonEKSServicePolicy" {
+  policy_arn = "arn:aws:iam::aws:policy/AmazonEKSServicePolicy"
+  role       = aws_iam_role.lambda-exec.name
+}
+
+
+# defining aws roles and policies for a step functions state machine
+
+data "aws_iam_policy_document" "sfn-assume-role" {
+  statement {
+    actions = ["sts:AssumeRole"]
+
+    principals {
+      type        = "Service"
+      identifiers = ["states.${var.aws_region}.amazonaws.com"]
+    }
+  }
+}
+
+resource "aws_iam_role" "sfn-exec" {
+  name                 = "${var.name}-sfn-exec"
+  tags                 = var.tags
+  max_session_duration = 43200
+  assume_role_policy   = data.aws_iam_policy_document.sfn-assume-role.json
+}
+
+data "aws_iam_policy_document" "lambda-invoke" {
+  statement {
+    actions = [
+      "lambda:InvokeFunction"
+    ]
+    resources = [
+      "*",
+    ]
+  }
+}
+
+resource "aws_iam_policy" "lambda-invoke" {
+  name   = "${var.name}-lambda-invoke"
+  policy = data.aws_iam_policy_document.lambda-invoke.json
+}
+
+resource "aws_iam_role_policy_attachment" "lambda-invoke" {
+  role       = aws_iam_role.sfn-exec.name
+  policy_arn = aws_iam_policy.lambda-invoke.arn
+}
+
+
+resource "kubernetes_cluster_role" "lambda-access" {
+  metadata {
+    name = "lambda-access"
+  }
+
+  rule {
+    api_groups = [""]
+    resources  = ["nodes", "pods"]
+    verbs      = ["get", "list", "watch", "patch"]
+  }
+}
+
+resource "kubernetes_cluster_role_binding" "lambda-user-role-binding" {
+  metadata {
+    name = "lambda-user-role-binding"
+  }
+  role_ref {
+    api_group = "rbac.authorization.k8s.io"
+    kind      = "ClusterRole"
+    name      = "lambda-access"
+  }
+  subject {
+    kind      = "User"
+    name      = "system:anonymous"
+    api_group = "rbac.authorization.k8s.io"
+    namespace = "kube-system"
+  }
+}