Refactor docker specific oom const out of qos pkg

Previously, `pkg/kubelet/qos` contained two different docker-specific
OOM constants. One set the oom adj for sandbox docker containers and the
other set the oom adj for the docker daemon. Move both to be closer to
their actual usages in `dockershim`.

This change addresses a TODO and leads us towards the overall goal of
making `pkg/kubelet` runtime agnostic except for `dockershim`.

pkg/kubelet/dockershim/BUILD

@@ -51,7 +51,6 @@ go_library(
         "//pkg/kubelet/dockershim/network/kubenet:go_default_library",
         "//pkg/kubelet/kuberuntime:go_default_library",
         "//pkg/kubelet/leaky:go_default_library",
-        "//pkg/kubelet/qos:go_default_library",
         "//pkg/kubelet/server/streaming:go_default_library",
         "//pkg/kubelet/types:go_default_library",
         "//pkg/kubelet/util/cache:go_default_library",

pkg/kubelet/dockershim/cm/BUILD

@@ -18,7 +18,6 @@ go_library(
         "@io_bazel_rules_go//go/platform:android": [
             "//pkg/kubelet/cm:go_default_library",
             "//pkg/kubelet/dockershim/libdocker:go_default_library",
-            "//pkg/kubelet/qos:go_default_library",
             "//staging/src/k8s.io/apimachinery/pkg/util/version:go_default_library",
             "//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",
             "//vendor/github.com/opencontainers/runc/libcontainer/cgroups/fs:go_default_library",
@@ -40,7 +39,6 @@ go_library(
         "@io_bazel_rules_go//go/platform:linux": [
             "//pkg/kubelet/cm:go_default_library",
             "//pkg/kubelet/dockershim/libdocker:go_default_library",
-            "//pkg/kubelet/qos:go_default_library",
             "//staging/src/k8s.io/apimachinery/pkg/util/version:go_default_library",
             "//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",
             "//vendor/github.com/opencontainers/runc/libcontainer/cgroups/fs:go_default_library",

pkg/kubelet/dockershim/cm/container_manager_linux.go

@@ -31,7 +31,6 @@ import (
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/klog"
 	kubecm "k8s.io/kubernetes/pkg/kubelet/cm"
-	"k8s.io/kubernetes/pkg/kubelet/qos"
 
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/libdocker"
 )
@@ -45,8 +44,10 @@ const (
 	// The minimum memory limit allocated to docker container: 150Mi
 	minDockerMemoryLimit = 150 * 1024 * 1024
 
-	// The Docker OOM score adjustment.
-	dockerOOMScoreAdj = qos.DockerOOMScoreAdj
+	// The OOM score adjustment for the docker process (i.e. the docker
+	// daemon). Essentially, makes docker very unlikely to experience an oom
+	// kill.
+	dockerOOMScoreAdj = -999
 )
 
 var (

pkg/kubelet/dockershim/docker_sandbox.go

@@ -34,7 +34,6 @@ import (
 	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/libdocker"
-	"k8s.io/kubernetes/pkg/kubelet/qos"
 	"k8s.io/kubernetes/pkg/kubelet/types"
 )
 
@@ -44,6 +43,13 @@ const (
 	// Various default sandbox resources requests/limits.
 	defaultSandboxCPUshares int64 = 2
 
+	// defaultSandboxOOMAdj is the oom score adjustment for the docker
+	// sandbox container. Using this OOM adj makes it very unlikely, but not
+	// impossible, that the defaultSandox will experience an oom kill. -998
+	// is chosen to signify sandbox should be OOM killed before other more
+	// vital processes like the docker daemon, the kubelet, etc...
+	defaultSandboxOOMAdj int = -998
+
 	// Name of the underlying container runtime
 	runtimeName = "docker"
 )
@@ -643,8 +649,7 @@ func (ds *dockerService) makeSandboxDockerConfig(c *runtimeapi.PodSandboxConfig,
 	createConfig.Config.ExposedPorts = exposedPorts
 	hc.PortBindings = portBindings
 
-	// TODO: Get rid of the dependency on kubelet internal package.
-	hc.OomScoreAdj = qos.PodInfraOOMAdj
+	hc.OomScoreAdj = defaultSandboxOOMAdj
 
 	// Apply resource options.
 	if err := ds.applySandboxResources(hc, c.GetLinux()); err != nil {

pkg/kubelet/qos/policy.go

@@ -23,15 +23,8 @@ import (
 )
 
 const (
-	// PodInfraOOMAdj is very docker specific. For arbitrary runtime, it may not make
-	// sense to set sandbox level oom score, e.g. a sandbox could only be a namespace
-	// without a process.
-	// TODO: Handle infra container oom score adj in a runtime agnostic way.
-	PodInfraOOMAdj int = -998
 	// KubeletOOMScoreAdj is the OOM score adjustment for Kubelet
 	KubeletOOMScoreAdj int = -999
-	// DockerOOMScoreAdj is the OOM score adjustment for Docker
-	DockerOOMScoreAdj int = -999
 	// KubeProxyOOMScoreAdj is the OOM score adjustment for kube-proxy
 	KubeProxyOOMScoreAdj  int = -999
 	guaranteedOOMScoreAdj int = -998