Infra Requirements

Overview

This page discusses the infrastructure requirements for DIGIT services. It also explains why DIGIT services are containerised and deployed on Kubernetes.

Requirements

DIGIT Infra is abstracted to Kubernetes which is an open-source containers orchestration platform that helps in abstracting a variety of infra types that are being available across each state, like Physical, VMs, on-premises clouds(VMware, OpenStack, Nutanix, etc.), commercial clouds (Google, AWS, Azure, etc.), SDC and NIC into a standard infra type. Essentially it unifies various infra types into a standard and single type of infrastructure and thus DIGIT becomes multi-cloud supported, portable, extensible, high-performant and scalable containerized workloads and services. This facilitates both declarative configuration and automation. Kubernetes services, eco-system, support and tools are widely available.

The basic need to provision Kubernetes Cluster

Kubernetes as such is a set of components that designated jobs of scheduling, controlling, monitoring

Master Cluster

  • 3 or more machines running one of:

    • Ubuntu 16.04+

    • Debian 9

    • CentOS 7

    • RHEL 7

    • Container Linux (tested with 1576.4.0)

  • 4 GB or more of RAM per machine (any less will leave little room for your apps)

  • 2 CPUs or more

User Cluster

  • 3 or more machines running one of:

    • Ubuntu 16.04+

    • Debian 9

    • CentOS 7

    • RHEL 7

    • Container Linux (tested with 1576.4.0)

  • 2 GB or more of RAM per machine (any less will leave little room for your apps)

  • 2 CPUs or more

  • Full network connectivity between all machines in the cluster (public or private network is fine)

  • Unique hostname, MAC address, and product_uuid for every node. Click here for more details.

  • Certain ports are open on your machines. See below for more details

  • Swap disabled. You MUST disable swap in order for the Kubelet to work properly

Verify the MAC Address and product_uuid Are Unique for Every Node

  • You can get the MAC address of the network interfaces using the command ip link or ifconfig -a

  • The product_uuid can be checked by using the command sudo cat /sys/class/dmi/id/product_uuid

It is very likely that hardware devices will have unique addresses, although some virtual machines may have identical values. Kubernetes uses these values to uniquely identify the nodes in the cluster. If these values are not unique to each node, the installation process may fail.

Check Network Adapters

If you have more than one network adapter, and your Kubernetes components are not reachable on the default route, we recommend you add IP route(s) so Kubernetes cluster addresses go via the appropriate adapter.

Check Required Ports

Master Cluster Master Node(s)

ProtocolDirectionPort RangePurpose

TCP

Inbound

6443*

Kubernetes API server

TCP

Inbound

2379-2380

etcd server client API

TCP

Inbound

10250

kubelet API

TCP

Inbound

10251

kube-scheduler

TCP

Inbound

10252

kube-controller-manager

TCP

Inbound

10255

Read-only kubelet API

Worker Node(s)& User Cluster Worker Nodes

ProtocolDirectionPort RangePurpose

TCP

Inbound

10250

kubelet API

TCP

Inbound

10255

Read-only kubelet API

TCP

Inbound

30000-32767

NodePort Services**

** Default port range for NodePort Services.

Any port numbers marked with * are overridable, so you will need to ensure any custom ports you provide are also open.

Complete Infra Specifications

Systems

Specification

Spec/Count

Comment

User Accounts/VPN

Dev, UAT and Prod Envs

3

User Roles

Admin, Deploy, ReadOnly

3

OS

Any Linux (preferably Ubuntu/RHEL)

All

Kubernetes as a managed service or VMs to provision Kubernetes

Managed Kubernetes service with HA/DRS

(Or) VMs with 2 vCore, 4 GB RAM, 20 GB Disk

If no managed k8s

3 VMs/env

Dev - 3 VMs

UAT - 3VMs

Prod - 3VMs

Kubernetes worker nodes or VMs to provision Kube worker nodes.

VMs with 4 vCore, 16 GB RAM, 20 GB Disk / per env

3-5 VMs/env

DEV - 3VMs

UAT - 4VMs

PROD - 5VMs

Storage (NFS/iSCSI)

Storage with backup, snapshot, dynamic inc/dec

1 TB/env

Dev - 1000 GB

UAT - 800 GB

PROD - 1.5 TB

VM Instance IOPS

Max throughput 1750 MB/s

1750 MS/s

Storage IOPS

Max throughput 1000 MB/s

1000 MB/s

Internet Speed

Min 100 MB - 1000MB/Sec (dedicated bandwidth)

Public IP/NAT or LB

Internet-facing 1 public ip per env

3

3 Ips

Availability Region

VMs from the different region is preferable for the DRS/HA

at least 2 Regions

Private vLan

Per env all VMs should within private vLan

3

Gateways

NAT Gateway, Internet Gateway, Payment and SMS gateway, etc

1 per env

Firewall

Ability to configure Inbound, Outbound ports/rules

Managed DataBase

(or) VM Instance

Postgres 12 above Managed DB with backup, snapshot, logging.

(Or) 1 VM with 4 vCore, 16 GB RAM, 100 GB Disk per env.

per env

DEV - 1VMs

UAT - 1VMs

PROD - 2VMs

CI/CD server self-hosted (or) Managed DevOps

Self Hosted Jenkins: Master, Slave (VM 4vCore, 8 GB each)

(Or) Managed CI/CD: NIC DevOps or AWS CodeDeploy or Azure DevOps

2 VMs (Master, Slave)

Nexus Repo

Self-hosted Artifactory Repo (Or) NIC Nexus Artifactory

1

DockerRegistry

DockerHub (Or) SelfHosted private docker reg

1

Git/SCM

GitHub (Or) Any Source Control tool

1

DNS

main domain & ability to add more sub-domain

1

SSL Certificate

NIC managed (Or) SDC managed SSL certificate per URL

2 URLs per env

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