#! /bin/bash

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ipaddlastnumber=21		######## HERE  HERE  HERE  HERE  HERE  HERE ####################

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## Run this script on a fresh new compute node. Must specify uniquely the $ipaddlastnumber for each node. The first shall be assigned ipaddlastnumber=21, the second ipaddlastnumber=22, etc. The assignment of ipaddlastnumber must be done at this stage manually


## 1
### centos_node-1of2.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 ###
DNS2=10.202.1.1
DNS3=10.202.1.2 
HOSTNAME=compute-0-$ipaddlastnumber
hostnamectl set-hostname $HOSTNAME
#### default values. dont change ###

#2
# Check the identities of the network cards. Select one as the 'eth0' (to guess) and then modify the corresponding /etc/sysconfig/network-scripts/ifcfg-$nc0
IPADDR=192.168.1.$ipaddlastnumber
nc0=$(lshw -class network | grep -E 'Ethernet interface|logical name' | grep 'logical name' | awk '{print $3}' | awk '!/vir/' |  tail -n1)
echo $nc0 'is chosen as the eth0, internal network port. To modify /etc/sysconfig/network-scripts/ifcfg-"$nc0" in the frontend.'
echo ''
ls /etc/sysconfig/network-scripts/ifcfg-$nc0

# The following code will replace the ifcfg-$nc0 with the desired content. The original ifcfg-$nc0 will be saved as ifcfg-$nc0.orig

cp /etc/sysconfig/network-scripts/ifcfg-$nc0 /etc/sysconfig/network-scripts/ifcfg-$nc0.orig


############################################################
## sample of original /etc/sysconfig/network-scripts/ifcfg-$nc0
############################################################
##----  TYPE=Ethernet
##----  PROXY_METHOD=none
##----  BROWSER_ONLY=no
##----  BOOTPROTO=dhcp
##----  DEFROUTE=yes
##----  IPV4_FAILURE_FATAL=no
##----  IPV6INIT=yes
##----  IPV6_AUTOCONF=yes
##----  IPV6_DEFROUTE=yes
##----  IPV6_FAILURE_FATAL=no
##----  IPV6_ADDR_GEN_MODE=stable-privacy
##----  NAME=p6p1
##----  UUID=263dd108-793c-4871-8d14-2ee236d4efb9
##----  DEVICE=p6p1
##----  ONBOOT=no
############################################################

# Apart from the last two lines HWADDR and UUID, the content in /sysconfig/network-scripts/ifcfg-$nc0 should be universal. 
# The following code will replace the ifcfg-$nc with the desired content. The original ifcfg-$nc0 will be saved as ifcfg-$nc0.orig

cp /etc/sysconfig/network-scripts/ifcfg-$nc0 /etc/sysconfig/network-scripts/ifcfg-$nc0.orig

# replacement:
sed -i 's/BOOTPROTO=dhcp/BOOTPROTO=static/g' /etc/sysconfig/network-scripts/ifcfg-$nc0
sed -i 's/dhcp/static/g' /etc/sysconfig/network-scripts/ifcfg-$nc0
sed -i 's/IPV6INIT="yes"/IPV6INIT="no"/g' /etc/sysconfig/network-scripts/ifcfg-$nc0
sed -i 's/DHCPCLASS=//g' /etc/sysconfig/network-scripts/ifcfg-$nc0
sed -i 's/ONBOOT=no/ONBOOT="yes"/g' /etc/sysconfig/network-scripts/ifcfg-$nc0

# append
echo 'IPADDR='$IPADDR >> /etc/sysconfig/network-scripts/ifcfg-$nc0
echo 'NETMASK=255.255.0.0' >> /etc/sysconfig/network-scripts/ifcfg-$nc0
echo 'PREFIX=16' >> /etc/sysconfig/network-scripts/ifcfg-$nc0
echo 'DNS1=127.0.0.1' >> /etc/sysconfig/network-scripts/ifcfg-$nc0
echo 'DOMAIN=local' >> /etc/sysconfig/network-scripts/ifcfg-$nc0
echo 'NM_CONTROLLED="yes"' >> /etc/sysconfig/network-scripts/ifcfg-$nc0
############################################################



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# 4 Configure the default gateway (the IP of the switch) and hostname in /etc/sysconfig/network file in current node
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mv /etc/sysconfig/network /etc/sysconfig/network.orig
touch /etc/sysconfig/network
echo 'NETWORKING=yes' >> /etc/sysconfig/network
echo 'GATEWAY=192.168.1.10' >> /etc/sysconfig/network
echo 'HOSTNAME='$HOSTNAME >> /etc/sysconfig/network


## 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_$IPADDR

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

### 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.$IPADDR $HOSTNAME.local $HOSTNAME >> /share/cluster/hosts

service network restart


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## 6 generate passwordless ssh for $user to-and-fro the current node and the frontend
##### $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

user=root
frontend=192.168.1.10

### generates a rsa key in the current compute node for $user
ssh-keygen -t rsa

### copy the rsa key of the $user in the current compute node to the frontend
ssh-copy-id -i $user/.ssh/id_rsa.pub $frontend

### remotely generates the rsa key for the $user in the frontend by ssh-ing from the current compute node.
ssh $user@$frontend "ssh-keygen -t rsa"

### remotely asks the rsa key for the $user in the frontend to be copied via ssh to the current compute node. 
HOSTNAME=$(cat /etc/hostname)
ssh $user@$frontend "ssh-copy-id -i $user/.ssh/id_rsa.pub $HOSTNAME"




reboot