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moby--moby/daemon/config_unix.go
Michael Crosby ee3ac3aa66 Add init process for zombie fighting
This adds a small C binary for fighting zombies.  It is mounted under
`/dev/init` and is prepended to the args specified by the user.  You
enable it via a daemon flag, `dockerd --init`, as it is disable by
default for backwards compat.

You can also override the daemon option or specify this on a per
container basis with `docker run --init=true|false`.

You can test this by running a process like this as the pid 1 in a
container and see the extra zombie that appears in the container as it
is running.

```c

int main(int argc, char ** argv) {
	pid_t pid = fork();
	if (pid == 0) {
		pid = fork();
		if (pid == 0) {
			exit(0);
		}
		sleep(3);
		exit(0);
	}
	printf("got pid %d and exited\n", pid);
	sleep(20);
}
```

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
2016-09-19 17:33:50 -07:00

141 lines
6.7 KiB
Go

// +build linux freebsd
package daemon
import (
"fmt"
"net"
"github.com/docker/docker/api/types"
"github.com/docker/docker/opts"
runconfigopts "github.com/docker/docker/runconfig/opts"
units "github.com/docker/go-units"
"github.com/spf13/pflag"
)
var (
defaultPidFile = "/var/run/docker.pid"
defaultGraph = "/var/lib/docker"
defaultExecRoot = "/var/run/docker"
)
// Config defines the configuration of a docker daemon.
// It includes json tags to deserialize configuration from a file
// using the same names that the flags in the command line uses.
type Config struct {
CommonConfig
// Fields below here are platform specific.
CgroupParent string `json:"cgroup-parent,omitempty"`
ContainerdAddr string `json:"containerd,omitempty"`
EnableSelinuxSupport bool `json:"selinux-enabled,omitempty"`
ExecRoot string `json:"exec-root,omitempty"`
RemappedRoot string `json:"userns-remap,omitempty"`
Ulimits map[string]*units.Ulimit `json:"default-ulimits,omitempty"`
Runtimes map[string]types.Runtime `json:"runtimes,omitempty"`
DefaultRuntime string `json:"default-runtime,omitempty"`
OOMScoreAdjust int `json:"oom-score-adjust,omitempty"`
Init bool `json:"init,omitempty"`
}
// bridgeConfig stores all the bridge driver specific
// configuration.
type bridgeConfig struct {
commonBridgeConfig
// Fields below here are platform specific.
EnableIPv6 bool `json:"ipv6,omitempty"`
EnableIPTables bool `json:"iptables,omitempty"`
EnableIPForward bool `json:"ip-forward,omitempty"`
EnableIPMasq bool `json:"ip-masq,omitempty"`
EnableUserlandProxy bool `json:"userland-proxy,omitempty"`
DefaultIP net.IP `json:"ip,omitempty"`
IP string `json:"bip,omitempty"`
FixedCIDRv6 string `json:"fixed-cidr-v6,omitempty"`
DefaultGatewayIPv4 net.IP `json:"default-gateway,omitempty"`
DefaultGatewayIPv6 net.IP `json:"default-gateway-v6,omitempty"`
InterContainerCommunication bool `json:"icc,omitempty"`
}
// InstallFlags adds flags to the pflag.FlagSet to configure the daemon
func (config *Config) InstallFlags(flags *pflag.FlagSet) {
// First handle install flags which are consistent cross-platform
config.InstallCommonFlags(flags)
config.Ulimits = make(map[string]*units.Ulimit)
config.Runtimes = make(map[string]types.Runtime)
// Then platform-specific install flags
flags.BoolVar(&config.EnableSelinuxSupport, "selinux-enabled", false, "Enable selinux support")
flags.StringVarP(&config.SocketGroup, "group", "G", "docker", "Group for the unix socket")
flags.Var(runconfigopts.NewUlimitOpt(&config.Ulimits), "default-ulimit", "Default ulimits for containers")
flags.BoolVar(&config.bridgeConfig.EnableIPTables, "iptables", true, "Enable addition of iptables rules")
flags.BoolVar(&config.bridgeConfig.EnableIPForward, "ip-forward", true, "Enable net.ipv4.ip_forward")
flags.BoolVar(&config.bridgeConfig.EnableIPMasq, "ip-masq", true, "Enable IP masquerading")
flags.BoolVar(&config.bridgeConfig.EnableIPv6, "ipv6", false, "Enable IPv6 networking")
flags.StringVar(&config.ExecRoot, "exec-root", defaultExecRoot, "Root directory for execution state files")
flags.StringVar(&config.bridgeConfig.IP, "bip", "", "Specify network bridge IP")
flags.StringVarP(&config.bridgeConfig.Iface, "bridge", "b", "", "Attach containers to a network bridge")
flags.StringVar(&config.bridgeConfig.FixedCIDR, "fixed-cidr", "", "IPv4 subnet for fixed IPs")
flags.StringVar(&config.bridgeConfig.FixedCIDRv6, "fixed-cidr-v6", "", "IPv6 subnet for fixed IPs")
flags.Var(opts.NewIPOpt(&config.bridgeConfig.DefaultGatewayIPv4, ""), "default-gateway", "Container default gateway IPv4 address")
flags.Var(opts.NewIPOpt(&config.bridgeConfig.DefaultGatewayIPv6, ""), "default-gateway-v6", "Container default gateway IPv6 address")
flags.BoolVar(&config.bridgeConfig.InterContainerCommunication, "icc", true, "Enable inter-container communication")
flags.Var(opts.NewIPOpt(&config.bridgeConfig.DefaultIP, "0.0.0.0"), "ip", "Default IP when binding container ports")
flags.BoolVar(&config.bridgeConfig.EnableUserlandProxy, "userland-proxy", true, "Use userland proxy for loopback traffic")
flags.BoolVar(&config.EnableCors, "api-enable-cors", false, "Enable CORS headers in the remote API, this is deprecated by --api-cors-header")
flags.MarkDeprecated("api-enable-cors", "Please use --api-cors-header")
flags.StringVar(&config.CgroupParent, "cgroup-parent", "", "Set parent cgroup for all containers")
flags.StringVar(&config.RemappedRoot, "userns-remap", "", "User/Group setting for user namespaces")
flags.StringVar(&config.ContainerdAddr, "containerd", "", "Path to containerd socket")
flags.BoolVar(&config.LiveRestoreEnabled, "live-restore", false, "Enable live restore of docker when containers are still running")
flags.Var(runconfigopts.NewNamedRuntimeOpt("runtimes", &config.Runtimes, stockRuntimeName), "add-runtime", "Register an additional OCI compatible runtime")
flags.StringVar(&config.DefaultRuntime, "default-runtime", stockRuntimeName, "Default OCI runtime for containers")
flags.IntVar(&config.OOMScoreAdjust, "oom-score-adjust", -500, "Set the oom_score_adj for the daemon")
flags.BoolVar(&config.Init, "init", false, "Run an init in the container to forward signals and reap processes")
config.attachExperimentalFlags(flags)
}
// GetRuntime returns the runtime path and arguments for a given
// runtime name
func (config *Config) GetRuntime(name string) *types.Runtime {
config.reloadLock.Lock()
defer config.reloadLock.Unlock()
if rt, ok := config.Runtimes[name]; ok {
return &rt
}
return nil
}
// GetDefaultRuntimeName returns the current default runtime
func (config *Config) GetDefaultRuntimeName() string {
config.reloadLock.Lock()
rt := config.DefaultRuntime
config.reloadLock.Unlock()
return rt
}
// GetAllRuntimes returns a copy of the runtimes map
func (config *Config) GetAllRuntimes() map[string]types.Runtime {
config.reloadLock.Lock()
rts := config.Runtimes
config.reloadLock.Unlock()
return rts
}
// GetExecRoot returns the user configured Exec-root
func (config *Config) GetExecRoot() string {
return config.ExecRoot
}
func (config *Config) isSwarmCompatible() error {
if config.ClusterStore != "" || config.ClusterAdvertise != "" {
return fmt.Errorf("--cluster-store and --cluster-advertise daemon configurations are incompatible with swarm mode")
}
if config.LiveRestoreEnabled {
return fmt.Errorf("--live-restore daemon configuration is incompatible with swarm mode")
}
return nil
}