Add oom_score_adj to set default oom score adj

docs/containers.conf.5.md

@@ -233,6 +233,10 @@ Options are:
 Create /etc/hosts for the container. By default, container engines manage
 /etc/hosts, automatically adding  the container's  own  IP  address.
 
+**oom_score_adj**=0
+
+Tune the host's OOM preferences for containers (accepts values from -1000 to 1000).
+
 **pidns**="private"
 
 Default way to to create a PID namespace for the container.

pkg/config/config.go

@@ -184,6 +184,10 @@ type ContainersConfig struct {
 	// NoHosts tells container engine whether to create its own /etc/hosts
 	NoHosts bool `toml:"no_hosts,omitempty"`
 
+	// OOMScoreAdj tunes the host's OOM preferences for containers
+	// (accepts values from -1000 to 1000).
+	OOMScoreAdj *int `toml:"oom_score_adj,omitempty"`
+
 	// PidsLimit is the number of processes each container is restricted to
 	// by the cgroup process number controller.
 	PidsLimit int64 `toml:"pids_limit,omitempty,omitzero"`

pkg/config/config_test.go

@@ -425,6 +425,7 @@ image_copy_tmp_dir="storage"`
 			gomega.Expect(err).To(gomega.BeNil())
 			gomega.Expect(dbBackend).To(gomega.BeEquivalentTo(DBBackendSQLite))
 			gomega.Expect(config.Containers.CgroupConf).To(gomega.Equal(cgroupConf))
+			gomega.Expect(*config.Containers.OOMScoreAdj).To(gomega.Equal(int(750)))
 		})
 
 		It("contents of passed-in file should override others", func() {

pkg/config/containers.conf

@@ -202,6 +202,10 @@ default_sysctls = [
 #
 #no_hosts = false
 
+# Tune the host's OOM preferences for containers
+# (accepts values from -1000 to 1000).
+#oom_score_adj = 0
+
 # Default way to to create a PID namespace for the container
 # Options are:
 # `private` Create private PID Namespace for the container.

pkg/config/testdata/containers_default.conf

@@ -81,6 +81,8 @@ label = true
 # limit is never exceeded.
 log_size_max = -1
 
+oom_score_adj = 750
+
 # Maximum number of processes allowed in a container.
 pids_limit = 2048