This revision is from 2024/06/25 00:16. You can Restore it.

Two scripts, one is the system service so that the ram disk is re-instated upon reboot, ram volatility is obviously the situation with ram disks and the ram disk script.

Setup RAM disk service on Linux

# Filename: setup-ramdisk.service
# /etc/systemd/system/setup-ramdisk.service
# sudo cp /home/x/ram_disk/setup-ramdisk.service /etc/systemd/system/setup-ramdisk.service
# sudo systemctl daemon-reload
# sudo systemctl enable setup-ramdisk
# sudo systemctl start setup-ramdisk
# After reboot check with df -h | grep ramdisk
# sudo systemctl status setup-ramdisk

[Unit]
Description=Setup RAM disk and start web server
After=network.target

[Service]
Type=oneshot
ExecStart=/home/x/ram_disk/setup-ramdisk.sh
RemainAfterExit=true

[Install]
WantedBy=multi-user.target
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The second script involves keeping a copy of linux as chrooted jail for a user. Alpine Linux is sufficiently small that its works for this purpose. The second program is named schroot, apt-get install schroot. Putting the ram disk in a chroot jail insures we do not use the disk at all, a lib or two could sneak under the radar causing a bottleneck.

#!/bin/bash

# Set variables
RAMDISK_SIZE="1G"
RAM_DISK="/mnt/ramdisk"

# Create the mount point if it doesn't exist
mkdir -p $RAM_DISK

# Mount the RAM disk
mount -t tmpfs -o size=$RAMDISK_SIZE tmpfs $RAM_DISK

# Configure schroot (not part of the script)
# sudo apt-get install schroot
# [jimbo]
# description=Chroot for username
# directory=/mnt/ramdisk
# users=jimbo
# root-groups=root

# Add filesystem
sudo tar -xzf /home/x/ram_disk/alpine-minirootfs-3.20.0-x86_64.tar.gz -C ${RAM_DISK}

# Setup special directories by binding them to the host system
sudo mount -t proc /proc  ${RAM_DISK}/proc
sudo mount -t sysfs /sys ${RAM_DISK}/sys
sudo mount --rbind /dev ${RAM_DISK}/dev
sudo mount --rbind /dev/pts ${RAM_DISK}/dev/pts
sudo mount --rbind /run ${RAM_DISK}/run

# Set permissions
sudo chmod 1777 ${RAM_DISK}/tmp

# Set up jimbo user
sudo schroot -c jimbo --run-session -- mkdir -p /home/jimbo
sudo schroot -c jimbo --run-session -- chown jimbo:jimbo /home/jimbo

# touch nginx pid file, nginx
mkdir -p /run/nginx
sudo touch /run/nginx/nginx.pid
sudo schroot -c jimbo --directory=/home/jimbo -- nginx

# Note: make sure /etc/resolve.conf has DNS value such as nameserver 8.8.8.8 and nameserver 8.8.4.4
# sudo mount --bind /run/systemd/resolve/resolv.conf ${RAM_DISK}/etc/resolv.conf

#echo "nameserver 8.8.8.8" | sudo tee ${RAM_DISK}/etc/resolv.conf
#echo "nameserver 8.8.4.4" | sudo tee -a ${RAM_DISK}/etc/resolv.conf
#echo "It works, cocksucker!" | sudo tee -a ${RAM_DISK}/var/www/localhost/htdocs/index.html

#sudo schroot -c jimbo
#sudo schroot -c jimbo --directory=/home/jimbo
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A more complex script removes the mounts, but requires MAKEDEV to be copied into alpine-minirootfs-3.20.0-x86_64.tar.gz

#!/bin/bash

# Set variables
RAMDISK_SIZE="1G"
RAM_DISK="/mnt/ramdisk"

# Create the mount point if it doesn't exist
mkdir -p $RAM_DISK

# Mount the RAM disk
mount -t tmpfs -o size=$RAMDISK_SIZE tmpfs $RAM_DISK

# Configure schroot
# sudo apt-get install schroot
# [jimbo]
# description=Chroot for username
# directory=/mnt/ramdisk
# users=jimbo
# root-groups=root
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1. Make filesystem

sudo tar -xzf /home/x/ram_disk/alpine-minirootfs-3.20.0-x86_64.tar.gz -C ${RAM_DISK}

1. Set permissions

sudo chmod 1777 ${RAM_DISK}/tmp

1. Make dev

mkdir -p ${RAM_DISK}/dev

sudo schroot -c jimbo -u root -- sh -c "cd /dev && /usr/sbin/MAKEDEV std"

sudo schroot -c jimbo --run-session -- mount -t dev dev /dev

1. Setup proc within the chroot, do not bind

mkdir -p ${RAM_DISK}/proc

sudo schroot -c jimbo --run-session -- mount -t proc proc /proc

1. Setup sys in ram, do not bind

mkdir -p ${RAM_DISK}/sys

sudo schroot -c jimbo --run-session -- mount -t sysfs sysfs /sys

1. Setup run in ram, do not bind, no mont required

mkdir -p ${RAM_DISK}/run

mkdir -p ${RAM_DISK}/run/nginx

sudo touch ${RAM_DISK}/run/nginx/nginx.pid

1. ################################################
1. Every program requires a pid to be made from this script
1. ################################################

1. Set up jimbo user

sudo schroot -c jimbo --run-session -- mkdir -p /home/jimbo

sudo schroot -c jimbo --run-session -- chown jimbo:jimbo /home/jimbo

1. Enter chroot and start services, run applications at boot

sudo schroot -c jimbo --directory=/home/jimbo -- nginx

1. Add permanent resolve.conf to alpine-minirootfs-3.20.0-x86_64.tar.gz
2. rather than generating it.
3. Note: make sure /etc/resolve.conf has DNS value such as nameserver 8.8.8.8 and nameserver 8.8.4.4
4. sudo mount --bind /run/systemd/resolve/resolv.conf ${RAM_DISK}/etc/resolv.conf
5. echo "nameserver 8.8.8.8" | sudo tee ${RAM_DISK}/etc/resolv.conf
6. echo "nameserver 8.8.4.4" | sudo tee -a ${RAM_DISK}/etc/resolv.conf
7. echo "It works, cock." | sudo tee -a ${RAM_DISK}/var/www/localhost/htdocs/index.html

1. How to login
2. sudo schroot -c jimbo
3. sudo schroot -c jimbo --directory=/home/jimbo