menhera.sh/README.md

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# menhera.sh
Start a RAM Linux system (Debian for now) without requiring physical access to your server.
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With `menhera.sh` you can:
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* format your system disk or create RAID
* install a new distro
* do important maintenance or backup with nobody writing to your root filesystem
* ...
with only SSH!
"menhera" is short for "mental healer".
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## WARNING
> I am not responsible for bricked devices, dead HDDs and SSDs, unreplied tickets, thermonuclear war, or you getting fired because your device is hacked to mine bitcoin. Please do some research if you have any concerns about this script before using it! YOU are choosing to run this script, and if you point the finger at me for messing up your device, I will laugh at you.
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## Dependencies
* Linux kernel: overlayfs and tmpfs support
* systemd
* squashfs-tools
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* curl
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## Usage
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Just run the script, and follow the instructions.
`menhera.sh` will try to download a new rootfs into the memory, replace the old rootfs and kill all processes reading the old rootfs. The old rootfs will be mounted to `/mnt/oldroot`. An example filesystem structure after running `menhera.sh` on my test VPS:
```
root@localhost:~# findmnt
TARGET SOURCE FSTYPE OPTIONS
/ overlay overlay rw,relatime,lowerdir=/tmp/menhera/newrootro,upperdir=/tmp/menhera/newrootrw,workdir=/tmp/menhera/overlayfs_workdir
├─/sys sysfs sysfs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/kernel/security securityfs securityfs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/fs/cgroup tmpfs tmpfs ro,nosuid,nodev,noexec,mode=755
│ │ └─/sys/fs/cgroup/...
│ └─/sys/kernel/debug debugfs debugfs rw,relatime
├─/proc proc proc rw,nosuid,nodev,noexec,relatime
├─/dev udev devtmpfs rw,nosuid,relatime,size=1014856k,nr_inodes=253714,mode=755
│ └─/dev/...
├─/run tmpfs tmpfs rw,nosuid,noexec,relatime,size=205236k,mode=755
│ └─/run/lock tmpfs tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k
├─/mnt/oldroot /dev/md0p1 ext4 rw,relatime,discard,data=ordered
└─/tmp tmpfs tmpfs rw,relatime
└─/tmp/menhera tmpfs tmpfs rw,relatime
└─/tmp/menhera/newrootro /dev/loop0 squashfs ro,relatime
```
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## Thanks
* This project is inspired by [marcan/takeover.sh](https://github.com/marcan/takeover.sh)
* The major code came from [a maintenance writeup on my blog](https://blog.swineson.me/debian-9-csm-online-convert-root-partition-to-raid/) (in Simp. Chinese)
* [xTom.com](https://xtom.com/) donated a VPS for my testing