Public Key Infrastructure - (step-certificate)

apt install wget

wget wget https://dl.smallstep.com/gh-release/cli/gh-release-header/v0.24.4/step-cli_0.24.4_amd64.deb

wget https://dl.smallstep.com/gh-release/certificates/gh-release-header/v0.24.2/step-ca_0.24.2_amd64.deb

dpkg -i step-cli_0.24.4_amd64.deb

dpkg -i step-ca_0.24.2_amd64.deb

Run manually

step ca init

vi /root/.step/password.txt

ca-password

step-ca $(step path)/config/ca.json

Run as a service

setcap CAP_NET_BIND_SERVICE=+eip $(which step-ca)

useradd --system --home /usr/local/step --shell /bin/bash step

mkdir -p /usr/local/step

chown -R step:step /usr/local/step

su step

step ca init

step ca provisioner add acme --type ACME

vi /usr/local/step/.step/password.txt

ca-password

exit

vi /etc/systemd/system/step-ca.service

[Unit]
Description=step-ca service
Documentation=https://smallstep.com/docs/step-ca
Documentation=https://smallstep.com/docs/step-ca/certificate-authority-server-production
After=network-online.target
Wants=network-online.target
StartLimitIntervalSec=30
StartLimitBurst=3
ConditionFileNotEmpty=/usr/local/step/.step/config/ca.json
ConditionFileNotEmpty=/usr/local/step/.step/password.txt

[Service]
Type=simple
User=step
Group=step
Environment=STEPPATH=/usr/local/step/.step
WorkingDirectory=/usr/local/step/.step
ExecStart=/usr/bin/step-ca config/ca.json --password-file password.txt
ExecReload=/bin/kill --signal HUP $MAINPID
Restart=on-failure
RestartSec=5
TimeoutStopSec=30
StartLimitInterval=30
StartLimitBurst=3

; Process capabilities & privileges
AmbientCapabilities=CAP_NET_BIND_SERVICE
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
SecureBits=keep-caps
NoNewPrivileges=yes

; Sandboxing
ProtectSystem=full
ProtectHome=true
RestrictNamespaces=true
RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
PrivateTmp=true
PrivateDevices=true
ProtectClock=true
ProtectControlGroups=true
ProtectKernelTunables=true
ProtectKernelLogs=true
ProtectKernelModules=true
LockPersonality=true
RestrictSUIDSGID=true
RemoveIPC=true
RestrictRealtime=true
SystemCallFilter=@system-service
SystemCallArchitectures=native
MemoryDenyWriteExecute=true
ReadWriteDirectories=/usr/local/step/.step/db

[Install]
WantedBy=multi-user.target

systemctl enable step-ca

systemctl start step-ca

On the client side

copy root_ca.crt to /usr/local/share/ca-certificates

sudo cp root_ca.crt /usr/local/share/ca-certificates

sudo update-ca-certificates

apt install certbot

certbot certonly --standalone -d test1.example.com --server https://pki1.example.com/acme/acme/directory

Renew certificates

certbot renew