okami101/blog
2
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 46 Wiki Activity

write swarm post

Browse Source
This commit is contained in:
Adrien Beaudouin
2022-02-18 00:08:46 +01:00
parent c09e83c93f
commit b980b2e267
2 changed files with 160 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

171
content/posts/2022-02-13-build-your-own-docker-swarm-cluster.md
View File

@ -26,7 +26,7 @@ So the prerequisites before continue :
* Have some knowledge on docker-compose setups
* Be comfortable with SSH terminal
* Registered for a [Hetzner Cloud account](https://accounts.hetzner.com/signUp)
* A custom domain, I'll use `example.org` here
* A custom domain, I'll use `okami101.io` here
* A account to a transactional mail provider as mailgun, sendgrid, sendingblue, etc.
{{< alert >}}
@ -211,6 +211,9 @@ Now we are ready to set up the above architecture !
# create private network
hcloud network create --name network-01 --ip-range 10.0.0.0/16
# create a subnet for the network
hcloud network add-subnet network-01 --type server --network-zone eu-central --ip-range 10.0.0.0/24
# create manager server
hcloud server create --name manager-01 --ssh-key swarm --image ubuntu-20.04 --type cx21 --location nbg1 --network network-01
@ -223,35 +226,151 @@ hcloud server create --name runner-01 --ssh-key swarm --image ubuntu-20.04 --typ
# create data server
hcloud server create --name data-01 --ssh-key swarm --image ubuntu-20.04 --type cx21 --location nbg1 --network network-01
# create the volume that will be used by gluster
hcloud volume create --name volume-01 --size 60 --location nbg1 --automount --server data-01
# create the volume that will be used by gluster and automount it to the data server (fstab will be already setted)
hcloud volume create --name volume-01 --size 60 --server data-01 --automount --format ext4
```
### Prepare the servers
```sh
# ssh to your server
hcloud server ssh manager-01
```
It's time to do the classic minimal boring viable security setup for each server. Use `hcloud server ssh xxxxxx-01` for ssh connect and do the same for each.
```sh
# ssh to your server
hcloud server ssh worker-01
# ensure last upgrades
apt update && apt upgrade -y && reboot
# create your default non root and sudoer user (swarm in this sample)
adduser swarm # enter any strong password at prompt
# set the user to sudoer group and sync the same ssh root key
usermod -aG sudo swarm
rsync --archive --chown=swarm:swarm ~/.ssh /home/swarm
# setting vim for personal taste and remove sudo password
update-alternatives --config editor
visudo # replace %sudo... line by %sudo ALL=(ALL:ALL) NOPASSWD:ALL
# finally change default ssh port by anything else
vim /etc/ssh/sshd_config # Port 2222
service ssh reload
```
### The firewall
{{< alert >}}
The change of SSH port is not only for better security, but also for allowing more later git ssh access into your custom git provider as GitLab, Gitea, etc. that go through Traefik 22 port, as it will far more practical.
{{< /alert >}}
Finally, test your new `swarm` user by using `hcloud server ssh --user swarm --port 2222 xxxxxx-01` for each server and be sure that the user can do commands as sudo before continue.
Then edit `/etc/hosts` file for each server accordingly in order to add private ips :
{{< tabs tabTotal="3" >}}
{{< tab tabName="manager-01" >}}
```txt
10.0.0.3 worker-01 sw-worker-01
10.0.0.4 runner-01 sw-runner-01
10.0.0.5 data-01 sw-data-01
```
{{< /tab >}}
{{< tab tabName="worker-01" >}}
```txt
10.0.0.2 manager-01
10.0.0.5 data-01
```
{{< /tab >}}
{{< tab tabName="runner-01" >}}
```txt
10.0.0.2 manager-01
10.0.0.5 data-01
```
{{< /tab >}}
{{< /tabs >}}
{{< alert >}}
IPs are only showed here as samples, use `hcloud server describe xxxxxx-01` in order to get the right private IP under `Private Net`.
{{< /alert >}}
### Prepare the DNS and final SSH config
Now use `hcloud server ip manager-01` to get the unique frontal IP address of the cluster that will be used for any entry point, including SSH. Then edit the DNS of your domain and apply this IP to a particular subdomain, as well as a wildcard subdomain. You will see later what this wildcard domain is it for. I will use `sw.okami101.io` as sample. It should be looks like next :
```txt
sw 3600 IN A 123.123.123.123
*.sw 43200 IN CNAME sw
```
As soon as the above DNS is applied, you should ping `sw.okami101.io` or any `xyz.sw.okami101.io` domains.
It's now time to finalize your local SSH config for optimal access. Go to `~/.ssh/config` and add following hosts (change *okami101.io* and *swarm* accordingly to your own setup) :
```ssh
Host sw
User swarm
Port 2222
HostName sw.okami101.io
Host sw-data-01
User swarm
HostName sw-data-01
ProxyCommand ssh sw -W %h:2222
Host sw-runner-01
User swarm
HostName sw-runner-01
ProxyCommand ssh sw -W %h:2222
Host sw-worker-01
User swarm
HostName sw-worker-01
ProxyCommand ssh sw -W %h:2222
```
And that's it ! You should now quickly ssh to these servers easily by `ssh sw`, `ssh sw-worker-01`, `ssh sw-runner-01`, `ssh sw-data-01`, which will be far more practical.
{{< alert >}}
Note as I only use the `sw.okami101.io` as unique endpoint for ssh access to all internal server, without need of external SSH access to servers different from `manager-01`. It's known as SSH proxy, which allows single access point for better security perspective by simply jumping from main SSH access.
{{< /alert >}}
### The firewall 🧱
Now it's time to finish this preparation section by putting some security.
You should never let any cluster without properly configured firewall. It's generally preferable to use the cloud provider firewall instead of standard `ufw` because more easy to manage, no risk of being stupidly blocked, and settled once and for all.
You need at least 2 firewalls :
1. One for external incoming for SSH and Traefik, you'll need a full set of rules, only enabled for `manager-01`
2. The second for block all any incoming requests applied to any servers different from the manager
1. One for external incoming for SSH and Traefik web standard ports. You'll need a full set of rules, and it will be only enabled for `manager-01`. The main SSH port will be IP whitelisted to your public IP only.
2. The second firewall is for block all **any** incoming requests applied to any servers different from the `manager-01`, even for SSH as we don't need it anymore thanks to above SSH proxy.
{{< alert >}}
You wonder how we can access to this servers then, at least for ssh.
Note as the Hetzner Cloud Firewall will not apply to the private network at all, as it's [already considered to be "secured"](https://docs.hetzner.com/cloud/firewalls/faq/#can-firewalls-secure-traffic-to-my-private-hetzner-cloud-networks) ! I hope so, but I'm pretty sure that it will be possible to set a firewall in private networks in the future as we can just believe Hetzner word for word.
How can be sure that any other internal client has no access to our private network ? Use `ufw` if you're paranoid about that...
{{< /alert >}}
Create the 2 firewalls as next :
{{< tabs tabTotal="2" >}}
{{< tab tabName="bash" >}}
```sh
# internal firewall to protect internal server from all external access
hcloud firewall create --name firewall-internal
hcloud firewall apply-to-resource firewall-internal --type server --server worker-01
hcloud firewall apply-to-resource firewall-internal --type server --server runner-01
hcloud firewall apply-to-resource firewall-internal --type server --server data-01
# external firewall to protect manager-01 with only required ports
# use the json file from the 2nd tab just above
hcloud firewall create --name firewall-external --rules-file firewall-rules.json
hcloud firewall apply-to-resource firewall-external --type server --server manager-01
```
{{< /tab >}}
{{< tab tabName="firewall-rules.json" >}}
```json
[
{
@ -286,14 +405,28 @@ You wonder how we can access to this servers then, at least for ssh.
"port": "2222",
"protocol": "tcp",
"source_ips": [
"123.123.123.123/32"
"xx.xx.xx.xx/32"
]
}
]
```
```sh
# prepare firewall
hcloud firewall create --name firewall-internal
hcloud firewall create --name firewall-external --rules-file firewall-rules.json
```
{{< /tab >}}
{{< /tabs >}}
{{< alert >}}
Adapt the 4st rule of `firewall-rules.json` accordingly to your own chosen SSH port and set your own public IP inside `source_ips` in place of `xx.xx.xx.xx` value for better security. In case you have dynamic IP, just remove this last rule.
{{< /alert >}}
You should have now good protection against any unintended external access with only few required ports to your `manager-01` server, aka :
* **2222** : the main SSH port, with IP whitelist
* **443** : the HTTPS port for Traefik, our main access for all of your web apps
* **80** : the HTTP port for Traefik, only required for proper HTTPS redirection
* **22** : the SSH standard port for Traefik, required for proper usage through you main Git provider container as GitLab / Gitea
## 1st conclusion
And that's finally it !
We've done all the boring nevertheless essential stuff of this tutorial by preparing the physical part before attacking the more interesting one with cluster initial installation.