Activating Debug Mode

To activate debug mode, you need to set the log level to debug. To do this, set the debug key to true in the daemon.json file. Normally, you can find this file under /etc/docker. If the file doesn't exist, you may need to create it.

{
  "debug": true
}

Possible values are debug, info, warn, error, fatal.

Restart the Docker daemon to apply the changes.

sudo systemctl restart docker

You will be able to see all of the actions Docker is doing (we ran dockerd here). For example, when you run docker run hello-world, you will see something like:

DEBUG[..] form data: {"AttachStderr":true,"AttachStdin":false,"AttachStdout":true,"Cmd":null,"Domainname":"","Entrypoint":null,"Env":null,"HostConfig":{"AutoRemove":false,"Binds":null,"BlkioDeviceReadBps":[],"BlkioDeviceReadIOps":[],"BlkioDeviceWriteBps":[],"BlkioDeviceWriteIOps":[],"BlkioWeight":0,"BlkioWeightDevice":[],"CapAdd":null,"CapDrop":null,"Cgroup":"","CgroupParent":"","CgroupnsMode":"","ConsoleSize":[49,85],"ContainerIDFile":"","CpuCount":0,"CpuPercent":0,"CpuPeriod":0,"CpuQuota":0,"CpuRealtimePeriod":0,"CpuRealtimeRuntime":0,"CpuShares":0,"CpusetCpus":"","CpusetMems":"","DeviceCgroupRules":null,"DeviceRequests":null,"Devices":[],"Dns":[],"DnsOptions":[],"DnsSearch":[],"ExtraHosts":null,"GroupAdd":null,"IOMaximumBandwidth":0,"IOMaximumIOps":0,"IpcMode":""

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