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authorMatthew Heon <matthew.heon@gmail.com>2018-09-14 16:56:14 -0400
committerGitHub <noreply@github.com>2018-09-14 16:56:14 -0400
commit77985bc25bde30bb8e4ed6abab02242bbb5c0612 (patch)
treeb9ea6bd1f024a3d4074acf1286f1b48003f9eac5
parenta7b6a0fd16e4b5f4a30a16e0ec1d5574925717ae (diff)
parent95a374100b8127846d9f4f4a4cf8d9a5b2229912 (diff)
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Merge pull request #1464 from mheon/optionally_disable_port_reservation
Add a way to disable port reservation
-rw-r--r--libpod.conf8
-rw-r--r--libpod/oci.go22
-rw-r--r--libpod/runtime.go32
3 files changed, 42 insertions, 20 deletions
diff --git a/libpod.conf b/libpod.conf
index cc4a10cff..dcfeb67cc 100644
--- a/libpod.conf
+++ b/libpod.conf
@@ -80,3 +80,11 @@ pause_image = "k8s.gcr.io/pause:3.1"
# Default command to run the pause container
pause_command = "/pause"
+
+# Determines whether libpod will reserve ports on the host when they are
+# forwarded to containers. When enabled, when ports are forwarded to containers,
+# they are held open by conmon as long as the container is running, ensuring that
+# they cannot be reused by other programs on the host. However, this can cause
+# significant memory usage if a container has many ports forwarded to it.
+# Disabling this can save memory.
+#enable_port_reservation = true
diff --git a/libpod/oci.go b/libpod/oci.go
index e1c0d1261..3838394cb 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -66,6 +66,7 @@ type OCIRuntime struct {
socketsDir string
logSizeMax int64
noPivot bool
+ reservePorts bool
}
// syncInfo is used to return data from monitor process to daemon
@@ -75,7 +76,7 @@ type syncInfo struct {
}
// Make a new OCI runtime with provided options
-func newOCIRuntime(name string, path string, conmonPath string, conmonEnv []string, cgroupManager string, tmpDir string, logSizeMax int64, noPivotRoot bool) (*OCIRuntime, error) {
+func newOCIRuntime(name string, path string, conmonPath string, conmonEnv []string, cgroupManager string, tmpDir string, logSizeMax int64, noPivotRoot bool, reservePorts bool) (*OCIRuntime, error) {
runtime := new(OCIRuntime)
runtime.name = name
runtime.path = path
@@ -85,6 +86,7 @@ func newOCIRuntime(name string, path string, conmonPath string, conmonEnv []stri
runtime.tmpDir = tmpDir
runtime.logSizeMax = logSizeMax
runtime.noPivot = noPivotRoot
+ runtime.reservePorts = reservePorts
runtime.exitsDir = filepath.Join(runtime.tmpDir, "exits")
runtime.socketsDir = filepath.Join(runtime.tmpDir, "socket")
@@ -311,15 +313,17 @@ func (r *OCIRuntime) createOCIContainer(ctr *Container, cgroupParent string) (er
cmd.Env = append(cmd.Env, fmt.Sprintf("_OCI_STARTPIPE=%d", 4))
cmd.Env = append(cmd.Env, fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir))
- ports, err := bindPorts(ctr.config.PortMappings)
- if err != nil {
- return err
- }
+ if r.reservePorts {
+ ports, err := bindPorts(ctr.config.PortMappings)
+ if err != nil {
+ return err
+ }
- // Leak the port we bound in the conmon process. These fd's won't be used
- // by the container and conmon will keep the ports busy so that another
- // process cannot use them.
- cmd.ExtraFiles = append(cmd.ExtraFiles, ports...)
+ // Leak the port we bound in the conmon process. These fd's won't be used
+ // by the container and conmon will keep the ports busy so that another
+ // process cannot use them.
+ cmd.ExtraFiles = append(cmd.ExtraFiles, ports...)
+ }
if rootless.IsRootless() {
ctr.rootlessSlirpSyncR, ctr.rootlessSlirpSyncW, err = os.Pipe()
diff --git a/libpod/runtime.go b/libpod/runtime.go
index 63b8c971e..736169932 100644
--- a/libpod/runtime.go
+++ b/libpod/runtime.go
@@ -164,6 +164,14 @@ type RuntimeConfig struct {
InfraImage string `toml:"infra_image"`
// InfraCommand is the command run to start up a pod infra container
InfraCommand string `toml:"infra_command"`
+ // EnablePortReservation determines whether libpod will reserve ports on
+ // the host when they are forwarded to containers.
+ // When enabled, when ports are forwarded to containers, they are
+ // held open by conmon as long as the container is running, ensuring
+ // that they cannot be reused by other programs on the host.
+ // However, this can cause significant memory usage if a container has
+ // many ports forwarded to it. Disabling this can save memory.
+ EnablePortReservation bool `toml:"enable_port_reservation"`
}
var (
@@ -190,16 +198,17 @@ var (
ConmonEnvVars: []string{
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
},
- CgroupManager: SystemdCgroupsManager,
- HooksDir: hooks.DefaultDir,
- StaticDir: filepath.Join(storage.DefaultStoreOptions.GraphRoot, "libpod"),
- TmpDir: "",
- MaxLogSize: -1,
- NoPivotRoot: false,
- CNIConfigDir: "/etc/cni/net.d/",
- CNIPluginDir: []string{"/usr/libexec/cni", "/usr/lib/cni", "/opt/cni/bin"},
- InfraCommand: DefaultInfraCommand,
- InfraImage: DefaultInfraImage,
+ CgroupManager: SystemdCgroupsManager,
+ HooksDir: hooks.DefaultDir,
+ StaticDir: filepath.Join(storage.DefaultStoreOptions.GraphRoot, "libpod"),
+ TmpDir: "",
+ MaxLogSize: -1,
+ NoPivotRoot: false,
+ CNIConfigDir: "/etc/cni/net.d/",
+ CNIPluginDir: []string{"/usr/libexec/cni", "/usr/lib/cni", "/opt/cni/bin"},
+ InfraCommand: DefaultInfraCommand,
+ InfraImage: DefaultInfraImage,
+ EnablePortReservation: true,
}
)
@@ -467,7 +476,8 @@ func makeRuntime(runtime *Runtime) (err error) {
ociRuntime, err := newOCIRuntime("runc", runtime.ociRuntimePath,
runtime.conmonPath, runtime.config.ConmonEnvVars,
runtime.config.CgroupManager, runtime.config.TmpDir,
- runtime.config.MaxLogSize, runtime.config.NoPivotRoot)
+ runtime.config.MaxLogSize, runtime.config.NoPivotRoot,
+ runtime.config.EnablePortReservation)
if err != nil {
return err
}