Running the Prerequisite Tool

The prerequisite tool

validates for environment readiness and also configures some of the system configurations to ensure a smooth and successful AppViewX deployment.
is a secure and reliable way to avoid any adverse effects on the environment.
logs all changes made to the environment configuration for auditing and troubleshooting purposes.

Sudo permissions are required to execute the tool. This utility can be executed from any of the nodes; either worker or master. It is available in github - prerequisite utility.

The table below lists all the validations and the possible configurations performed by the prerequisite tool.


System Configuration	Validation	Configuration	Reason
Validating the system architecture - x86_64	Yes	No	System level configuration
Validating RAM in worker nodes and master nodes	Yes	No	System level configuration
Validating CPU cores in worker nodes and master nodes	Yes	No	System level configuration
Validating disk space	Yes	No	System level configuration
Verifying ports communication	Yes	No	System level configuration
Cleaning up the process running on ports	Yes	Yes	NA
Validating OS	Yes	No	OS - RHEL/ CentOS/ Ubuntu
Validating OS version	Yes	No	Validating version of OS
Installing rpm/ deb dependency packages	Yes	Yes	NA
Validation for chrony and chrony sync status	Yes	Yes	NA
Validating NTP and NTP sync status	Yes	Yes	NA
Validate Runc version	Yes	Yes	NA
Validating Selinux status	Yes	Yes	NA
Validating IP of node	Yes	No	Validating the provided Ip of the nodes
Validating user id value	Yes	No	User id check
Validating umask value	Yes	Yes	NA
Validating ulimit value	Yes	Yes	NA
Validating Openssl version	Yes	No	Openssl version validation
Validating time difference between the servers	Yes	Yes	NA
Validating ftype in xfs_info	Yes	No	Checking supported file system
noexec for /tmp	Yes	No	Checking permission for the /tmp directory
Validate IPV6 service	Yes	Yes	NA
Check vm.max_map_count value	Yes	Yes	NA
Server latency check	Yes	No	Latency check in and between the servers
Validate loopback IP - 127.0.0.1	Yes	Yes	NA
Validate Firewalld service	Yes	Yes	NA
Network interface lookup	Yes	No	Validating the network interface
Packet analyser	Yes	No	capture, inspect, and analyze network traffic
Analysing received packets	Yes	No	capture, inspect, and analyze network traffic
Validation of Crontab of user	Yes	Yes	NA
Validate puppet status	Yes	Yes	NA
Validate IP Tables	Yes	Yes	NA
Validate ip_forwarding	Yes	Yes	NA
Validate bridging	Yes	Yes	NA
Validating proxy variable values	Yes	Yes	NA
Cross validating SSH communication	Yes	No	Validation of ssh to nodes
Validating the GID	Yes	No	Verify that the GID we're validating corresponds to an existing group on the system
Validating User Id between the user of all servers	Yes	No	Ensuring user id assignment across servers is same
Validating group Id between the user of all servers	Yes	No	Ensuring GID assignment across servers is same

To run the prerequisite tool:

Create a folder to download the prerequisite.tar.gz Eg:
```
mkdir -p <folder_name>
```
Download and extract the prerequisite.tar.gz file to the created folder. To extract the file use the command below.
```
tar -xvf prerequisite.tar.gz
```

To update the hosts_template execute the command below. Specify the AppViewX IP address of the VMs (master and worker nodes), DNS servers and gateway address, and users in the file.

vi hosts_template

Add the following values in the host_template parameters below.


Parameters	Description
NODES	It is the IP addresses of all the nodes. You can enter multiple comma separated values. Example:`NODE = 192.111.222.333`
USERS	The username for the nodes and must have sudo privileges. Example:`USERS = appviewx` In case of multi-node setup, enter the sudo username with comma separated value the number of times equivalent to number of AppViewX nodes (including masters & workers). for example, for a 2 DC 7 node setup, we need to enter the username 7 times - appviewx,appviewx,appviewx,appviewx,appviewx,appviewx,appviewx. Note: Usually for a multi-node setup the username for all nodes (master and slave) must be the same.
MASTER_NODES	IP address of the master node Example:`MASTER_NODES = 192.111.222.444`
WORKER_NODES	IP address of the master node Example:`WORKER_NODES = 192.111.222.555`
NEW_INSTALLATION_PATH	Example:`NEW_INSTALLATION_PATH = /home/appviewx/appviewx_cluster`
USER_GENERATED_PEM	If you require to do a password-less installation of AppViewX, enter the value as True. If set to False, then you will be prompted to enter the password after you execute the `./prerequisite` command Example:`USER_GENERATED_PEM = TRUE`
PRIVATE_KEY_FILE_PATH	Specify the path where the pem file is saved. Example:`PRIVATE_KEY_FILE_PATH = /tmp/user_generated_private.pem`
CHRONY_SYNC	If you require the time sync in the nodes enter the value as true. Example:`CHRONY_SYNC = TRUE`
CHRONY_SERVER	Specify the chrony server to be used for time sync. Example:`CHRONY_SERVER = abcs.appviewx.net`
HTTP_PROXY	If internet is not present in the nodes then use the http proxy to install the rpm/deb packages in the nodes. Example:`HTTP_PROXY = https://192.999.888.777:1234`
HTTPS_PROXY	If internet is not present in the nodes then use the http proxy to install the rpm/deb packages in the nodes. Example:`HTTPS_PROXY = https://192.999.888.777:1234`

Execute the following command:
```
./prerequisite
```
The following options are displayed.
1. Enter the choice as 1 or 2
2. If you enter 1, then the tool validates all the system configurations specified in the table. If the configurations are not as per expectations the errors/failures will be displayed as shown below.
  Post the validation the results are displayed as report in the format below. It shows the Summary, Host-Level Execution Status, and the Task-Level Execution Status (Failed). (The screenshots shown are for a multi-node setup.)
3. If you enter 2, then the tool will install the configurations as specified in the table and also validates all the system configurations.
  - It stops the firewall service.
  - It installs the rpm/deb package if not already installed.
4. To view the execution logs for both validate and configure, refer the prerequisite_execution.log file that is present in the location where the prerequisite file is present.