Centos Server installation script

This a simple script to install a server and 4 virtual machines based on Centos 8.1. The script can be a series of instructions for me to execute. Following are the features of the server: 1. Common aspects of linux VMs a) All servers must be secure, no unidentified ports or protocols open. Capable of being exposed to the internet. b) No unnecessary packages installed, minimal installation. c) All servers and hypervisor are centos 8.1 based, 64 bit and are headless. d) Packages to be installed d.1. UFW – requires EPEL repo d.2. JDK 13 d.3. Nginx d.4. Postgresql 12.1 e) Syslog streamed out f) No UDP ports opened except for DHCP g) Internal bridge enables all nodes to receive inbound connections from the internet. h) All nodes registered in dyn dns, Route 53 preferably, as subdomains – dev, test, prd, cicd i) All nodes have TLS certs installed for HTTPS j) All nodes have UFW to configure internal firewalls 2. Server install 2.1. 4 VMs on one server a) 64 Gb RAM, 8 Core Processor, 1Tb PCIE 4.0 SSD b) Centos 64 bit Hypervisor c) All VMs are externally visible on the network, so a bridge/switch is needed in the host OS d) All VMs will request through DHCP their own external IPs 2.2. PRD VM a) 32 GB Ram b) 4 Cores c) 256 Gb drive d) Depending upon the performance we can increase the Prd server capacity e) Syslog streamed out to cicd f) IPTables configured to permit the following: i) 2 outgoing HTTPS ports, one for API and other for static content ii) Incoming NTP Port open iii) Outgoing syslog iv) No outgoing ssh v) SSH from Home VLAN only vi) Sftp incoming from CI_CD only 2.3. Test VM a) 8 GB Ram b) 1 Cores c) 128 Gb drive d) FW configured to permit the following: I. 2 outgoing HTTPS ports, one for API and other for static content II. Incoming NTP Port open III. Outgoing syslog IV. No outgoing ssh V. Sftp from CI_CD and Home VLAN only VI. Sftp incoming from CI_CD only 2.4. Dev VM a) 8 GB Ram b) 1 Cores c) 128 Gb drive d) FW configured to permit the following: I. SSH only from local IPs II. 2 outgoing HTTPS ports, one for API and other for static content III. Incoming NTP Port open IV. No outgoing ssh V. Sftp incoming from CI_CD only 2.5. CICD VM a) Used for various administration, team services etc. b) 8 GB Ram c) 2 Cores d) 256 Gb drive e) Git, Jenkins f) IPTables configured to permit the following: I. SSH only from Home Vlan only II. 2 outgoing HTTPS ports, one for API and other for static content III. Incoming NTP Port open IV. Outgoing 80 & 443