Docker on mac vs linux

Posted by nancy on Apr 20, 2020 — 1 min read...

🐳Docker is different on Mac and Linux systems. Docker directly leverages the kernel of the host system on Linux. On the other hand, Mac does not provide a Linux kernel, so Docker runs on a small Linux VM running on a mac. Due to this, there are many differences.

Cannot access container IPs directly

On Linux let's try to inspect a running docker image :

ubuntu@primary:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND              CREATED             STATUS              PORTS               NAMES
a230855dd7d2        httpd               "httpd-foreground"   17 seconds ago      Up 16 seconds       80/tcp              determined_saha
ubuntu@primary:~$ sudo docker inspect determined_saha

Let's curl the IP :

"IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]
ubuntu@primary:~$ curl 172.17.0.2
<html><body><h1>It works!</h1></body></html>

However on mac when hitting the IP address of the container we get :

➜ curl 172.17.0.3
curl: (7) Failed to connect to 172.17.0.3 port 80: Operation timed out

Curl times out because the container is running inside the VM and not sharing the network with the mac.

Docker on mac vs linux

Cannot access container IPs directly

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