Running a dotnet Core Linux daemon

Apr 5, 2018

Environment

• Ubuntu 16.04 using SystemD

Create application

# Create application
mkdir dnsvc
cd dnsvc
dotnet new console

# Change Program.cs
cat > Program.cs <<EOF
using System;
using System.Threading;


namespace dnsvc
{
  class Program
  {
    static void Main(
      string[] args)
    {
      var sleep = 3000;
      if (args.Length > 0) { int.TryParse(args[0], out sleep); }
      while (true)
      {
        Console.WriteLine($"Working, pausing for {sleep}ms");
        Thread.Sleep(sleep);
      }
    }
  }
}
EOF

# Restore dependencies
dotnet restore

# Publish to a local bin sub directory
dotnet publish --configuration Release --output bin

# Run local to verify all is good
dotnet ./bin/dnsvc.dll

Create SystemD service file

Will run the application from the bin sub directory for now

cat > dnsvc.service <<EOF
[Unit]
Description=Demo service
After=network.target

[Service]
ExecStart=/usr/bin/dotnet $(pwd)/bin/dnsvc.dll 5000
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

Configure SystemD so it is aware of the new service

# Copy service file to a System location
sudo cp dnsvc.service /lib/systemd/system

# Reload SystemD and enable the service, so it will restart on reboots
sudo systemctl daemon-reload 
sudo systemctl enable dnsvc

# Start service
sudo systemctl start dnsvc 

# View service status
systemctl status dnsvc

Tail the service log

stdout output can be examined with journalctl

journalctl --unit dnsvc --follow

Stopping and restarting the service

# Stop service
sudo systemctl stop dnsvc 
systemctl status dnsvc 

# Restart the service
sudo systemctl start dnsvc 
systemctl status dnsvc