responsive design

public/posts/Putting hungry minecraft servers to sleep/post.md

@@ -1,7 +1,9 @@
 2
 Minecraft Rust Async Networking Proxy CRIU
 \title
+
 \toc
+
 # Minecraft servers are HUNGRY
 
 They hunger for your ram and your cpu. This makes it either expensive or
@@ -50,21 +52,65 @@ minecraft protocol instead of HTTP.
 
 ## The Minecraft protocol
 
-Minecraft implements its own protocol consistent of packets. My first idea was to see if anybody had created a
-rust library for dealing with minecraft packets. 
+Minecraft implements its own protocol consistent of packets. My first idea 
+was to see if anybody had created a rust library for dealing with minecraft 
+packets. 
 
-While some did exist, most of them where unfinished or couldn't do what I wanted. [One crate](https://www.youtube.com/watch?v=E4WlUXrJgy4)
-was useful for seeing how an implementation of parsing packets was done, but ultimately I had to write my own parser.
+While some did exist, most of them where unfinished or couldn't do what I 
+wanted. [One crate](https://www.youtube.com/watch?v=E4WlUXrJgy4) was useful 
+for seeing how an implementation of parsing packets was done, but ultimately 
+I had to write my own parser.
 
-*images of minecraft protocol*
+***images of minecraft protocol***
 
 ## Detecting the subdomain
 
-Luckily for me, the Minecraft procotol sends the full address it is trying to connect to during the handshake. This meant that I simply
-had to parse the handshake and extract the subdomain from the address, see if it matches any configured server, and then redirect all
-traffic to the internal port that server runs on.
+Luckily for me, the Minecraft procotol sends the full address it is trying to
+connect to during the handshake. This meant that I simply had to parse the 
+handshake and extract the subdomain from the address, see if it matches any
+configured server, and then redirect all traffic to the internal port that 
+server runs on.
 
-*code explanation*
+***code explanation***
+
+***show images of hibernation and starting***
+
+![A server that is starting](/posts/Putting hungry minecraft servers to sleep/starting.png "A server in the middle of starting")
+![A server that is hibernating](/posts/Putting hungry minecraft servers to sleep/hibernating.png "An empty server thats been hibernated")
+
+I've talked a bunch about this hibernation, but how does it actually work?
+
+# cat /proc/$(ps aux | grep server.jar) > hibernation.txt
+
+Finally being able to connect to the server it was time for the next item on the list.
+
+<p style="text-align: center">✨**Hibernation**✨</p>
+
+Now, instead of closing the server and restarting it when a player joined I
+wanted to hibernate the server and unhibernate it when someone joined.
+
+I had a feeling this would be possible as this is basically how hibernation
+works for your system; it saves the memory to disk and loads it into memory
+again upon boot.
+
+After a bit of searching I found [CRIU](https://criu.org/Main_Page), a program
+capable of suspending another program to disk.
+
+Not only does it save the memory, it also saves all the file descriptors the
+program was using (and fails with a million cryptic error messages if any of the
+files where changed during hibernation)
+
+There was a Rust crate for CRIU, however it was poorly documented and didnt support
+all the command line arguments I needed, so I resorted to calling the binary.
+
+This led to the program halting until the unhibernated server closed again, but
+it was fixed with a simple fork.
+
+The only downside to this approach is that CRIU requires root access in order
+to read the memory and file descriptors of another process.  
+Running your minecraft server as root is probably not the smartest idea...
+
+My solution was to not care about it and hope for the best :D
 
 # Why aren't my chunks loading?