#! /bin/bash

# Mandatory requirement: The local network IP address for the node running this script has been correctly set (e.g., 192.168.1.xx) and is already connected to the frontend at 192.168.1.10 via the local network (a local switch), presumbably during the centos8 installation of this node.


ipaddlastnumber=$(ifconfig | grep 255.255.0.0 |awk '{ print $2}' | awk -F'.' '{print $4}')

## 1
### nfs_node.txt
### Configuring compute nodes (NFS clients)
### reference: https://www.itzgeek.com/how-tos/linux/centos-how-tos/how-to-setup-nfs-server-on-centos-7-rhel-7-fedora-22.html
#### default values. dont change ###
HOSTNAME=compute-0-$ipaddlastnumber
hostnamectl set-hostname $HOSTNAME
#### default values. dont change ###


## 5. Doing NFS configuration in current node
# Check NFS Share
# Before mounting the NFS share, check the NFS shares available on the NFS server by running the following command on the NFS client.

showmount -e 192.168.1.10

# Mount the shared directory in the NFS clients (the share directory in the frontend is supposed to be /export/share
mkdir /share
mount 192.168.1.10:/export/share /share

#Verify the mounted share on the NFS client using mount command.

mount | grep nfs

#Also, you can use the df -hT command to check the mounted NFS share.

df -hT

#Create a file on the mounted directory to verify the read and write access on NFS share.

touch /share/test_$HOSTNAME

#If the above command returns no error, you have working NFS setup

# To mount the shares automatically on every reboot, you would need to modify /etc/fstab file of your NFS client.

cp /etc/fstab /etc/fstab.orig
echo '192.168.1.10:/export/share /share nfs   nosuid,rw,sync,hard,intr  0  0' >> /etc/fstab

# Reload the entries in the modified /etc/fstab, by using the mount command:	
mount -av

### replace /etc/hosts file by that shared in /share/cluster/hosts, then add to hosts the identify of current node
mv /etc/hosts /etc/hosts.orig
ln -s /share/cluster/hosts /etc/
echo 192.168.1.$ipaddlastnumber $HOSTNAME.local $HOSTNAME c$ipaddlastnumber >> /share/cluster/hosts
cat /share/cluster/hosts | sort | uniq > temp
mv temp /share/cluster/hosts


#### customize /etc/ssh in a fresh node, so that ssh can work seamlessly

# edit /etc/ssh/ssh_config, so that it reads 'GSSAPIAuthentication no'

# edit /etc/ssh/sshd_config, so that it reads 'GSSAPIAuthentication no \ UseDNS no'

#edit /etc/resolv.conf, so that it reads 'search local \ nameserver 192.168.1.10'. This line could be overwritten when setting the eth0 using NetworkManager.
#### end of customize /etc/ssh in a fresh node


### customize the root for the present node
mkdir -p /state/partition1
chmod -R 777 /state/partition1
if [[ -e ~/.ssh/id_rsa.pub ]]; then echo "pub rsa exists. Will not creat any."; else ssh-keygen -t rsa; fi
sh /share/apps/local/bin/gen_bashrc.txt
source ~/.bashrc

### if the nfs mount has been successful at this stage, the node should be able to see the shared directory /share/apps/local/bin/
sh /share/apps/local/bin/gen_bashrc-root
source ~/.bashrc

# edit /etc/ssh/ssh_config, so that it reads 'GSSAPIAuthentication no'
# edit /etc/ssh/sshd_config, so that it reads 'GSSAPIAuthentication no \ UseDNS no'

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.orig
sed -i 's/GSSAPIAuthentication yes/GSSAPIAuthentication no/g' /etc/ssh/sshd_config
sed -i 's/UseDNS yes/UseDNS no/g' /etc/ssh/sshd_config

sed -i 's/GSSAPIAuthentication yes/GSSAPIAuthentication no/g' /etc/ssh/ssh_config
sed -i 's/UseDNS yes/UseDNS no/g' /etc/ssh/ssh_config
#### end of customize /etc/ssh in a fresh node


sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-Linux-*
sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.epel.cloud|g' /etc/yum.repos.d/CentOS-Linux-*

dnf install -y epel-release
dnf install -y sshpass  ## note: this line will work if the internet connection to this local node is connected during the centos8 installation.

rpm -ivh /share/apps/configrepo/sshpass-1.06-2.el7.x86_64.rpm
basic_packages_dnf.txt