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moby--moby/daemon/config/config_unix.go

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// +build linux freebsd
package config // import "github.com/docker/docker/daemon/config"
import (
"fmt"
Implement none, private, and shareable ipc modes Since the commit d88fe447df0e8 ("Add support for sharing /dev/shm/ and /dev/mqueue between containers") container's /dev/shm is mounted on the host first, then bind-mounted inside the container. This is done that way in order to be able to share this container's IPC namespace (and the /dev/shm mount point) with another container. Unfortunately, this functionality breaks container checkpoint/restore (even if IPC is not shared). Since /dev/shm is an external mount, its contents is not saved by `criu checkpoint`, and so upon restore any application that tries to access data under /dev/shm is severily disappointed (which usually results in a fatal crash). This commit solves the issue by introducing new IPC modes for containers (in addition to 'host' and 'container:ID'). The new modes are: - 'shareable': enables sharing this container's IPC with others (this used to be the implicit default); - 'private': disables sharing this container's IPC. In 'private' mode, container's /dev/shm is truly mounted inside the container, without any bind-mounting from the host, which solves the issue. While at it, let's also implement 'none' mode. The motivation, as eloquently put by Justin Cormack, is: > I wondered a while back about having a none shm mode, as currently it is > not possible to have a totally unwriteable container as there is always > a /dev/shm writeable mount. It is a bit of a niche case (and clearly > should never be allowed to be daemon default) but it would be trivial to > add now so maybe we should... ...so here's yet yet another mode: - 'none': no /dev/shm mount inside the container (though it still has its own private IPC namespace). Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd need to make 'private' the default mode, but unfortunately it breaks the backward compatibility. So, let's make the default container IPC mode per-daemon configurable (with the built-in default set to 'shareable' for now). The default can be changed either via a daemon CLI option (--default-shm-mode) or a daemon.json configuration file parameter of the same name. Note one can only set either 'shareable' or 'private' IPC modes as a daemon default (i.e. in this context 'host', 'container', or 'none' do not make much sense). Some other changes this patch introduces are: 1. A mount for /dev/shm is added to default OCI Linux spec. 2. IpcMode.Valid() is simplified to remove duplicated code that parsed 'container:ID' form. Note the old version used to check that ID does not contain a semicolon -- this is no longer the case (tests are modified accordingly). The motivation is we should either do a proper check for container ID validity, or don't check it at all (since it is checked in other places anyway). I chose the latter. 3. IpcMode.Container() is modified to not return container ID if the mode value does not start with "container:", unifying the check to be the same as in IpcMode.IsContainer(). 3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified to add checks for newly added values. [v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997] [v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833] [v4: addressed the case of upgrading from older daemon, in this case container.HostConfig.IpcMode is unset and this is valid] [v5: document old and new IpcMode values in api/swagger.yaml] [v6: add the 'none' mode, changelog entry to docs/api/version-history.md] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-06-27 17:58:50 -04:00
containertypes "github.com/docker/docker/api/types/container"
"github.com/docker/docker/opts"
"github.com/docker/go-units"
)
Implement none, private, and shareable ipc modes Since the commit d88fe447df0e8 ("Add support for sharing /dev/shm/ and /dev/mqueue between containers") container's /dev/shm is mounted on the host first, then bind-mounted inside the container. This is done that way in order to be able to share this container's IPC namespace (and the /dev/shm mount point) with another container. Unfortunately, this functionality breaks container checkpoint/restore (even if IPC is not shared). Since /dev/shm is an external mount, its contents is not saved by `criu checkpoint`, and so upon restore any application that tries to access data under /dev/shm is severily disappointed (which usually results in a fatal crash). This commit solves the issue by introducing new IPC modes for containers (in addition to 'host' and 'container:ID'). The new modes are: - 'shareable': enables sharing this container's IPC with others (this used to be the implicit default); - 'private': disables sharing this container's IPC. In 'private' mode, container's /dev/shm is truly mounted inside the container, without any bind-mounting from the host, which solves the issue. While at it, let's also implement 'none' mode. The motivation, as eloquently put by Justin Cormack, is: > I wondered a while back about having a none shm mode, as currently it is > not possible to have a totally unwriteable container as there is always > a /dev/shm writeable mount. It is a bit of a niche case (and clearly > should never be allowed to be daemon default) but it would be trivial to > add now so maybe we should... ...so here's yet yet another mode: - 'none': no /dev/shm mount inside the container (though it still has its own private IPC namespace). Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd need to make 'private' the default mode, but unfortunately it breaks the backward compatibility. So, let's make the default container IPC mode per-daemon configurable (with the built-in default set to 'shareable' for now). The default can be changed either via a daemon CLI option (--default-shm-mode) or a daemon.json configuration file parameter of the same name. Note one can only set either 'shareable' or 'private' IPC modes as a daemon default (i.e. in this context 'host', 'container', or 'none' do not make much sense). Some other changes this patch introduces are: 1. A mount for /dev/shm is added to default OCI Linux spec. 2. IpcMode.Valid() is simplified to remove duplicated code that parsed 'container:ID' form. Note the old version used to check that ID does not contain a semicolon -- this is no longer the case (tests are modified accordingly). The motivation is we should either do a proper check for container ID validity, or don't check it at all (since it is checked in other places anyway). I chose the latter. 3. IpcMode.Container() is modified to not return container ID if the mode value does not start with "container:", unifying the check to be the same as in IpcMode.IsContainer(). 3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified to add checks for newly added values. [v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997] [v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833] [v4: addressed the case of upgrading from older daemon, in this case container.HostConfig.IpcMode is unset and this is valid] [v5: document old and new IpcMode values in api/swagger.yaml] [v6: add the 'none' mode, changelog entry to docs/api/version-history.md] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-06-27 17:58:50 -04:00
const (
// DefaultIpcMode is default for container's IpcMode, if not set otherwise
DefaultIpcMode = "shareable" // TODO: change to private
)
// 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
// These fields are common to all unix platforms.
CommonUnixConfig
// Fields below here are platform specific.
CgroupParent string `json:"cgroup-parent,omitempty"`
EnableSelinuxSupport bool `json:"selinux-enabled,omitempty"`
RemappedRoot string `json:"userns-remap,omitempty"`
Ulimits map[string]*units.Ulimit `json:"default-ulimits,omitempty"`
CPURealtimePeriod int64 `json:"cpu-rt-period,omitempty"`
CPURealtimeRuntime int64 `json:"cpu-rt-runtime,omitempty"`
OOMScoreAdjust int `json:"oom-score-adjust,omitempty"`
Init bool `json:"init,omitempty"`
InitPath string `json:"init-path,omitempty"`
SeccompProfile string `json:"seccomp-profile,omitempty"`
ShmSize opts.MemBytes `json:"default-shm-size,omitempty"`
NoNewPrivileges bool `json:"no-new-privileges,omitempty"`
Implement none, private, and shareable ipc modes Since the commit d88fe447df0e8 ("Add support for sharing /dev/shm/ and /dev/mqueue between containers") container's /dev/shm is mounted on the host first, then bind-mounted inside the container. This is done that way in order to be able to share this container's IPC namespace (and the /dev/shm mount point) with another container. Unfortunately, this functionality breaks container checkpoint/restore (even if IPC is not shared). Since /dev/shm is an external mount, its contents is not saved by `criu checkpoint`, and so upon restore any application that tries to access data under /dev/shm is severily disappointed (which usually results in a fatal crash). This commit solves the issue by introducing new IPC modes for containers (in addition to 'host' and 'container:ID'). The new modes are: - 'shareable': enables sharing this container's IPC with others (this used to be the implicit default); - 'private': disables sharing this container's IPC. In 'private' mode, container's /dev/shm is truly mounted inside the container, without any bind-mounting from the host, which solves the issue. While at it, let's also implement 'none' mode. The motivation, as eloquently put by Justin Cormack, is: > I wondered a while back about having a none shm mode, as currently it is > not possible to have a totally unwriteable container as there is always > a /dev/shm writeable mount. It is a bit of a niche case (and clearly > should never be allowed to be daemon default) but it would be trivial to > add now so maybe we should... ...so here's yet yet another mode: - 'none': no /dev/shm mount inside the container (though it still has its own private IPC namespace). Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd need to make 'private' the default mode, but unfortunately it breaks the backward compatibility. So, let's make the default container IPC mode per-daemon configurable (with the built-in default set to 'shareable' for now). The default can be changed either via a daemon CLI option (--default-shm-mode) or a daemon.json configuration file parameter of the same name. Note one can only set either 'shareable' or 'private' IPC modes as a daemon default (i.e. in this context 'host', 'container', or 'none' do not make much sense). Some other changes this patch introduces are: 1. A mount for /dev/shm is added to default OCI Linux spec. 2. IpcMode.Valid() is simplified to remove duplicated code that parsed 'container:ID' form. Note the old version used to check that ID does not contain a semicolon -- this is no longer the case (tests are modified accordingly). The motivation is we should either do a proper check for container ID validity, or don't check it at all (since it is checked in other places anyway). I chose the latter. 3. IpcMode.Container() is modified to not return container ID if the mode value does not start with "container:", unifying the check to be the same as in IpcMode.IsContainer(). 3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified to add checks for newly added values. [v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997] [v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833] [v4: addressed the case of upgrading from older daemon, in this case container.HostConfig.IpcMode is unset and this is valid] [v5: document old and new IpcMode values in api/swagger.yaml] [v6: add the 'none' mode, changelog entry to docs/api/version-history.md] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-06-27 17:58:50 -04:00
IpcMode string `json:"default-ipc-mode,omitempty"`
// ResolvConf is the path to the configuration of the host resolver
ResolvConf string `json:"resolv-conf,omitempty"`
}
// BridgeConfig stores all the bridge driver specific
// configuration.
type BridgeConfig struct {
commonBridgeConfig
// These fields are common to all unix platforms.
commonUnixBridgeConfig
// 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"`
UserlandProxyPath string `json:"userland-proxy-path,omitempty"`
FixedCIDRv6 string `json:"fixed-cidr-v6,omitempty"`
}
// IsSwarmCompatible defines if swarm mode can be enabled in this config
func (conf *Config) IsSwarmCompatible() error {
if conf.ClusterStore != "" || conf.ClusterAdvertise != "" {
return fmt.Errorf("--cluster-store and --cluster-advertise daemon configurations are incompatible with swarm mode")
}
if conf.LiveRestoreEnabled {
return fmt.Errorf("--live-restore daemon configuration is incompatible with swarm mode")
}
return nil
}
Implement none, private, and shareable ipc modes Since the commit d88fe447df0e8 ("Add support for sharing /dev/shm/ and /dev/mqueue between containers") container's /dev/shm is mounted on the host first, then bind-mounted inside the container. This is done that way in order to be able to share this container's IPC namespace (and the /dev/shm mount point) with another container. Unfortunately, this functionality breaks container checkpoint/restore (even if IPC is not shared). Since /dev/shm is an external mount, its contents is not saved by `criu checkpoint`, and so upon restore any application that tries to access data under /dev/shm is severily disappointed (which usually results in a fatal crash). This commit solves the issue by introducing new IPC modes for containers (in addition to 'host' and 'container:ID'). The new modes are: - 'shareable': enables sharing this container's IPC with others (this used to be the implicit default); - 'private': disables sharing this container's IPC. In 'private' mode, container's /dev/shm is truly mounted inside the container, without any bind-mounting from the host, which solves the issue. While at it, let's also implement 'none' mode. The motivation, as eloquently put by Justin Cormack, is: > I wondered a while back about having a none shm mode, as currently it is > not possible to have a totally unwriteable container as there is always > a /dev/shm writeable mount. It is a bit of a niche case (and clearly > should never be allowed to be daemon default) but it would be trivial to > add now so maybe we should... ...so here's yet yet another mode: - 'none': no /dev/shm mount inside the container (though it still has its own private IPC namespace). Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd need to make 'private' the default mode, but unfortunately it breaks the backward compatibility. So, let's make the default container IPC mode per-daemon configurable (with the built-in default set to 'shareable' for now). The default can be changed either via a daemon CLI option (--default-shm-mode) or a daemon.json configuration file parameter of the same name. Note one can only set either 'shareable' or 'private' IPC modes as a daemon default (i.e. in this context 'host', 'container', or 'none' do not make much sense). Some other changes this patch introduces are: 1. A mount for /dev/shm is added to default OCI Linux spec. 2. IpcMode.Valid() is simplified to remove duplicated code that parsed 'container:ID' form. Note the old version used to check that ID does not contain a semicolon -- this is no longer the case (tests are modified accordingly). The motivation is we should either do a proper check for container ID validity, or don't check it at all (since it is checked in other places anyway). I chose the latter. 3. IpcMode.Container() is modified to not return container ID if the mode value does not start with "container:", unifying the check to be the same as in IpcMode.IsContainer(). 3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified to add checks for newly added values. [v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997] [v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833] [v4: addressed the case of upgrading from older daemon, in this case container.HostConfig.IpcMode is unset and this is valid] [v5: document old and new IpcMode values in api/swagger.yaml] [v6: add the 'none' mode, changelog entry to docs/api/version-history.md] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-06-27 17:58:50 -04:00
func verifyDefaultIpcMode(mode string) error {
const hint = "Use \"shareable\" or \"private\"."
dm := containertypes.IpcMode(mode)
if !dm.Valid() {
return fmt.Errorf("Default IPC mode setting (%v) is invalid. "+hint, dm)
}
if dm != "" && !dm.IsPrivate() && !dm.IsShareable() {
return fmt.Errorf("IPC mode \"%v\" is not supported as default value. "+hint, dm)
}
return nil
}
// ValidatePlatformConfig checks if any platform-specific configuration settings are invalid.
func (conf *Config) ValidatePlatformConfig() error {
return verifyDefaultIpcMode(conf.IpcMode)
}