Merge branch 'pi-docker-swarm' into 'main'

Pi docker swarm

See merge request AHMZA/blog!3

content/posts/building-a-docker-swarm-with-pis.md

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+---
+title: Building a Docker Swarm With Pi's
+date: 2021-12-12T17:23:32Z
+author: "ahmza"
+draft: true
+weight: 
+
+tags: ["Homelab","Docker","Docker Swarm","Raspberry Pi","Pi4"]
+description: "Pis are very capable computers, when banded together they're almost unstoppable"
+canonicalURL: "https://blog.ahmza.com/Page%28/posts/building-a-docker-swarm-with-pis.md%29"
+
+cover:
+    image: "/img/pi-docker-swarm/pi-swarm.gif" # image path/url
+    alt: "Pi Docker Swarm" # alt text
+    caption: "<text>" # display caption under cover
+    relative: false # when using page bundles set this to true
+showtoc: true
+searchHidden: false
+---
+
+## **Intro**
+The _Raspberry Pi_ from it's first iteration has been a great hit.
+Adopted by many as the computer of choice for projects, and for
+very good reason. The Pi is a fully fledged computer that fits in
+your pocket and the most recent edition has blown fans away with
+the flagship model boasting an ARM64 CPU and 8GB of RAM.
+
+Now one _Raspberry Pi 4 8GB_ is more than powerful enough for most
+workloads and in some cases totally unnecessary, **so you may even
+get away with a single 4GB model**. However taking into consideration
+their relatively low price and power consumption why not go all out
+and build a cluster.
+
+> **You can never have too many _Raspberry Pis_, just
+not enough Ideas**
+
+My excuse to build a Pi cluster is, I would like to migrate the
+services currently running on a **bare metal server that sucks
+a lot of power to a low power solution.** What better way to do that
+than a Pi cluster.
+
+### **My Setup**
+* 4 x _Raspberry Pi 4 8GB_
+* 4 x 32GB SD cards
+* 4 x PoE hats
+* 1 x 5 port PoE Switch
+
+![Insert Image of cluster here]()
+
+### **Point of this post**
+Hopefully after following this post you will have setup _Docker
+swarm_ on a cluster of Pis **- stay even if you currently only have
+one -** and understand how to bend it to your will 🦾. 
+
+### **Why** ***Docker Swarm*** 🧐
+While we can manage each docker node - _Raspberry Pi_ - individually
+, **_Docker swarm_ enables us to manage all the devices from a single
+main node** making managing the cluster a lot easier.
+
+Think of _Docker swarm_ as a set of 🤖 hands which will run tasks on
+each individual node for us. These tasks can consist of:
+* Cluster Management
+* Deployment and Scaling across the cluster
+* Multi-host networking
+* load balancing
+* etc...
+
+### **Well why not** ***Kubernetes***
+Although _Kubernetes_ is awesome, **it adds a bunch of complexity that
+is simply not needed in a home lab environment** where we only have
+a small cluster. As well as that, from my experience creating
+```docker-compose``` files is a lot easier than writing manifests.
+**_Docker swarm_ can do everything I want it to and requires less
+effort** which is great if you're like me 🥱 😂
+
+### **Required Stuff**
+> The links below are reccomendations/stuff I used
+* [_Raspberry Pi_ 4B](https://thepihut.com/products/raspberry-pi-4-model-b?variant=31994565689406) (Reccomend 4-8 @ 8GB)
+* [_Raspberry Pi_ PoE Hats](https://thepihut.com/products/power-over-ethernet-poe-hat-d-for-raspberry-pi) (If you can find the [PoE+](https://thepihut.com/products/raspberry-pi-poe-plus-hat) version get them)
+* [Cluster Case](https://thepihut.com/products/cluster-case-for-raspberry-pi) (Get any case you want)
+* [PoE switch](https://www.amazon.co.uk/gp/product/B076982FVC/) (Get one that has enough ports for the nuber of pis you want)
+* [RJ45 Ethernet Cable](https://www.amazon.co.uk/gp/product/B00C4U030G) (Reccomend short cables as it will look neater)
+* [Micro SD cards](https://www.amazon.co.uk/gp/product/B08J4HJ98L) (Get enough cards for the number of Pis, Get the biggest cards you can afford)
+
+**This is without a doubt an expensive project**, however in my eyes
+it's the cost of another server 😂 and the best part about this
+project is **you can add to the cluster over time** spreding the cost
+which is how I managed to purchase all the hardware. A suggestion
+would be to **buy equipment that allows you room to grow** so an 8 port
+PoE switch instead of a 4 port if you know you will scale to 8
+nodes
+
+If you build this then you can safely say another server is not
+needed. This cluster should be more than capable to serve all your
+home needs even if you only have 2 nodes. Put it this way, if you
+have 4 8GB nodes then you have a combined total of:
+* 32GB of RAM
+* 16 physical CPU cores @ 1.5GHz
+
+#### **Money Saving Tips**
+* Just get 1-2 nodes to start
+* cut PoE and use normal power cables
+* Use Raspberry Pis with less memmory eg 4GB
+* Grab a really cheap case or make one using [these](https://www.amazon.co.uk/dp/B091KJNZLB/)
+* Use smaller SD Cards try not to go below 32GB (Reccomended 64GB If money saved elsewhere)
+
+## **BUILD TIME !!**
+Pull yourself up by your bootstraps were jumping into this one
+runnig 💨
+
+### **Image the SD Cards**
+So interesting fact the CPUs used in the raspberry pi 4 use an ARM64
+archetecture. When looking for images of Raspbian you will only find
+32bit variants which will work however will not make use of all the
+hardware which is just a waste. 64bit images exist however are well
+hidden, Dont fear 😨 **you can download the latest images from the 
+[raspberrypi.org index](https://downloads.raspberrypi.org/raspios_arm64/images/)**
+
+To write the cards I use the [**Raspberry Pi imager**](https://www.raspberrypi.com/software/).
+once you have **rpi-imager** installed and you have the 64bit raspbian
+image, open ```sudo rpi-imager``` and on the "CHOOSE OS" section go to
+the bottom and select use custom image.
+
+> We dont need to unzip the file as the tool is clever enough to
+handle that for us
+
+**Before removing the SD card, mount the boot partition - usually the
+first partition, look for a file called cmdline.txt - and create an
+empty file called ssh** ```sudo touch ssh``` this basically enables
+SSH on the Pis first boot allowing us to access the Pis in a totally
+headless manner.
+
+### Assemble the cluster
+So assembly is very dependant on the kit you bought, and more
+often than not the stuff needed here comes with instructions or is
+self explanitory. So go ahead and assemble the cluster 🛠
+
+**There is an order of operations that I reccomend:**
+* Install PoE hats onto the Pis
+* Install the SD Cards into the Pis
+* Assemble the case and install Pis
+* plug in ethernet cables
+
+**Now allow the Pis to boot for a few minutes so it can resize the
+file system**
+
+### **Sort out the Network bits**
+This is the easy part, there are two methods we can use to set a
+static IP address, one is on your DHCP server and the other is on
+the device itself. Personally I prefer to set static IPs on the
+device itself so I will cover that here.
+
+To find the current ip of your Pis you can go to your DHCP server
+and look for the DHCP leases for the Pis.
+
+**SSH to the Pi** then open and edit the following files
+* /etc/hosts
+    * edit this line with your hostname: ```127.0.1.1  mainpi```
+* /etc/hostname
+    * edit this file with your hostname: ```mainpi```
+* /etc/dhcpcd.conf
+    * knowing we will be using only static IPs here I delete
+    everything in the file add the following
+    *   ```
+        interface eth0
+        static ip_address=10.10.10.20/24
+        static routers=10.10.10.1
+        static domain_name_servers=10.10.10.1
+        ```
+**Now reboot the pi** ```sudo shutdown -r now```
+
+