Migrating the Backend Server System to Ubuntu Server

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What happened?
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I was happily using CentOS 7, but then I learned that Red Hat is going to crack down on us free-riders (I feel like I was force-fed a mouthful of 💩). So, for the sustainable development of the server (actually, I’m just bored during the holidays), I’m reinstalling the system and updating the ancient cheat sheet. Let’s begin!

Install OS
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Installation version: Ubuntu server 20.04 LTS Just follow the instructions. The username and password required during installation are for the normal account that will be used for login later. If you need to perform operations with elevated privileges, you need to use the sudo command, and the password is the password of your own account.

Config OpenSSH
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During the installation phase, you will be prompted whether to install OpenSSH. At the same time, you need to enable the firewall and set the port:

sudo ufw enable
sudo allow ssh
sudo ufw reload

Check the current status:

sudo ufw status

Swap mirror
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Reference: https://mirrors.tuna.tsinghua.edu.cn/help/ubuntu/

Change the package installation manager settings file:

sudo vim /etc/apt/sources.list

Then add the Tuna source according to the prompts.

First update
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sudo apt update
# Update software list
sudo apt dist-upgrade
# Update software, running upgrade alone may cause the system to be updated

Set up auto-update
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Reference: https://help.ubuntu.com/community/AutomaticSecurityUpdates

sudo dpkg-reconfigure --priority=low unattended-upgrades

Use the default settings (check once a day).

Set up Router
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Because I was completely “broken” by network bridging and NAT, I decided in a fit of anger: Virtualize an OpenWRT in the system!

(Updated on 2022/2/7) Found a project: lakinduakash / linux-wifi-hotspot, which can deploy a simple wireless router in one step.

Add ppa package and install:

sudo add-apt-repository ppa:lakinduakash/lwh
sudo apt install linux-wifi-hotspot

Manually install dnsmasq (if using NAT mode):

apt install dnsmasq

Edit /etc/create_ap.conf (example file)

GATEWAY=192.168.6.1
SHARE_METHOD=nat
COUNTRY=CN
WIFI_IFACE=wlp7s0
INTERNET_IFACE=enp1s0
SSID=MyAccessPoint
PASSPHRASE=MyPassword

Use systemctl start create_ap to start the AP, and systemctl enable create_ap to start it on boot.

Set up serial login with getty
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sudo cp /usr/lib/systemd/system/serial-getty@.service /etc/systemd/system/serial-getty@ttyS0.service
sudo systemctl daemon-reload
sudo systemctl start serial-getty@ttyS0.service
sudo systemctl enable serial-getty@ttyS0.service

Usage of ufw
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Check the current status and open ports:

sudo ufw status

Open ports:

sudo ufw allow 8000/tcp
sudo ufw allow 7000
sudo ufw allow from 192.168.6.0/24 to any port 25577

Delete added rules:

# List the numbers of existing rules
sudo ufw status numbered
# Delete rules by number
sudo ufw delete 3
sudo ufw reload

Set up Certbot
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Reference: https://certbot.eff.org/lets-encrypt/ubuntufocal-other

sudo snap install core; sudo snap refresh core
sudo snap install --classic certbot
sudo ln -s /snap/bin/certbot /usr/bin/certbot

Set up mumble
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Reference: https://wiki.mumble.info/

Installation:

sudo add-apt-repository ppa:mumble/release
sudo apt-get update
sudo apt-get install mumble-server
sudo dpkg-reconfigure mumble-server

Open port 64738. Configure the /etc/mumble-server.ini file. The service name is mumble-server.

Set up Netdata
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Reference: https://learn.netdata.cloud/docs/

Due to strange connection problems (referring to the wall of Github), the offline installation mode is used.

curl -s https://my-netdata.io/kickstart.sh > kickstart.sh

# Netdata tarball
curl -s https://api.github.com/repos/netdata/netdata/releases/latest | grep "browser_download_url.*tar.gz" | cut -d '"' -f 4 | wget -qi -

# Netdata checksums
curl -s https://api.github.com/repos/netdata/netdata/releases/latest | grep "browser_download_url.*txt" | cut -d '"' -f 4 | wget -qi -

# Netdata dependency handling script
# It's strange that it often fails and needs to be created manually
wget -q - https://raw.githubusercontent.com/netdata/netdata/master/packaging/installer/install-required-packages.sh

# go.d plugin
# For binaries for OS types and architectures not listed on [go.d releases](https://github.com/netdata/go.d.plugin/releases/latest), kindly open a github issue and we will do our best to serve your request
export OS=$(uname -s | tr '[:upper:]' '[:lower:]') ARCH=$(uname -m | sed -e 's/i386/386/g' -e 's/i686/386/g' -e 's/x86_64/amd64/g' -e 's/aarch64/arm64/g' -e 's/armv64/arm64/g' -e 's/armv6l/arm/g' -e 's/armv7l/arm/g' -e 's/armv5tel/arm/g') && curl -s https://api.github.com/repos/netdata/go.d.plugin/releases/latest | grep "browser_download_url.*${OS}-${ARCH}.tar.gz" | cut -d '"' -f 4 | wget -qi -

# go.d configuration
curl -s https://api.github.com/repos/netdata/go.d.plugin/releases/latest | grep "browser_download_url.*config.tar.gz" | cut -d '"' -f 4 | wget -qi -

Copy the file to the server and grant execution permission:

# Unsafe, should not use 0777 permission
sudo chmod -R 0777 /tmp/netdata

Run:

cd /tmp/netdata
sudo bash ./kickstart.sh --local-files /tmp/netdata/netdata-(version-number-here).tar.gz /tmp/netdata/sha256sums.txt /tmp/netdata/go.d.plugin-(version-number-here).(OS)-(architecture).tar.gz /tmp/netdata/config.tar.gz /tmp/netdata/install-required-packages.sh --disable-telemetry

Tip: The problem that often occurs during installation is install-required-packages.sh, which requires special attention. Then modify the configuration file /etc/netdata/netdata.conf. When configuring SSL, there is a chance that the certificate file cannot be read (mainly privkey.pem). You need to refer to https://certbot.eff.org/docs/using.html#where-are-my-certificates to configure the file permissions.

Set up NP-Client
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Reference: https://ehang-io.github.io/

First, copy the pre-downloaded npc file to /tmp/npc, and create the configuration file /etc/np-client.conf:

[common]
server_addr=cloud.ip:8024
conn_type=kcp
vkey=you_vkey_here
auto_reconnection=true
crypt=false
compress=false

Use the command to install:

cd /tmp/npc
sudo ./npc install -config=/etc/np-client.conf

sudo npc start

Set up Java and Minecraft
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Install openjdk (latest):

sudo apt install default-jdk

Older versions of Minecraft require Java 8, which you need to download the binary file from the Oracle official website. Reference /etc/systemd/system/*.service file: Java 8:

[Unit]
Description=Minecraft Server with Java 8
After=network-online.target
Wants=network-online.target

[Service]
User=minecraft
WorkingDirectory=/usr/local/mc_1_7_10/
ExecStart=/usr/local/jre1.8.0_271/bin/java -jar /usr/local/mc_1_7_10/forge-1.7.10-10.13.4.1558-1.7.10-universal.jar nogui

[Install]
WantedBy=multi-user.target

OpenJDK:

[Unit]
Description=Minecraft Server
After=network-online.target
Wants=network-online.target

[Service]
User=minecraft
WorkingDirectory=/usr/local/mc_1_17/
ExecStart=/usr/bin/java -jar /usr/local/mc_1_17/server.jar nogui

[Install]
WantedBy=multi-user.target

Remember to open the port:

# Minecraft main port
sudo ufw allow 25565
# Minecraft Rcon control port
sudo ufw allow 25577

Set up Zerotier
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Lazy, no one uses it, so I won’t do it for now.

Reference: https://www.zerotier.com/download/

Set up PPPOE
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Install the configuration program:

sudo apt install pppoeconf

Configure:

sudo pppoeconf

Start and disconnect:

# Connect
pon dsl-provider
# Disconnect
poff dsl-provider

What happened?#

Install OS#

Config OpenSSH#

Swap mirror#

First update#

Set up auto-update#

Set up Router#

Set up serial login with getty#

Usage of ufw#

Set up Certbot#

Set up mumble#

Set up Netdata#

Set up NP-Client#

Set up Java and Minecraft#

Set up Zerotier#

Set up PPPOE#