Use the /var/lib/calico/nodename file if it exists

projectcalico · Mar 2, 2018 · af68821 · af68821
1 parent bf7d348
commit af68821
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Showing 3 changed files with 56 additions and 18 deletions.
diff --git a/calico.go b/calico.go
@@ -38,8 +38,6 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-var nodename string
-
 func init() {
 	// This ensures that main runs only on main thread (thread group leader).
 	// since namespace ops (unshare, setns) are done for a single thread, we
@@ -56,8 +54,16 @@ func cmdAdd(args *skel.CmdArgs) error {
 
 	utils.ConfigureLogging(conf.LogLevel)
 
+	if conf.RequireNodenameFile {
+		// Configured to use the nodename file - don't start until it exists.
+		if _, err := os.Stat("/var/lib/calico/nodename"); err != nil {
+			// Nodename file doesn't exist - return an error.
+			return fmt.Errorf("/var/lib/calico/nodename is missing - is calico/node running?")
+		}
+	}
+
 	// Allow the nodename to be overridden by the network config
-	nodename = utils.DetermineNodename(conf)
+	nodename := utils.DetermineNodename(conf)
 
 	// Extract WEP identifiers such as pod name, pod namespace (for k8s), containerID, IfName.
 	wepIDs, err := utils.GetIdentifiers(args, nodename)
@@ -374,6 +380,14 @@ func cmdDel(args *skel.CmdArgs) error {
 
 	utils.ConfigureLogging(conf.LogLevel)
 
+	if conf.RequireNodenameFile {
+		// Configured to use the nodename file - don't start until it exists.
+		if _, err := os.Stat("/var/lib/calico/nodename"); err != nil {
+			// Nodename file doesn't exist - return an error.
+			return fmt.Errorf("/var/lib/calico/nodename is missing - is calico/node running?")
+		}
+	}
+
 	// Allow the nodename to be overridden by the network config
 	nodename := utils.DetermineNodename(conf)
 

diff --git a/types/types.go b/types/types.go
@@ -69,23 +69,24 @@ type NetConf struct {
 		IPv4Pools  []string `json:"ipv4_pools,omitempty"`
 		IPv6Pools  []string `json:"ipv6_pools,omitempty"`
 	} `json:"ipam,omitempty"`
-	MTU            int        `json:"mtu"`
-	Hostname       string     `json:"hostname"`
-	Nodename       string     `json:"nodename"`
-	DatastoreType  string     `json:"datastore_type"`
-	EtcdAuthority  string     `json:"etcd_authority"`
-	EtcdEndpoints  string     `json:"etcd_endpoints"`
-	LogLevel       string     `json:"log_level"`
-	Policy         Policy     `json:"policy"`
-	Kubernetes     Kubernetes `json:"kubernetes"`
-	Args           Args       `json:"args"`
-	EtcdScheme     string     `json:"etcd_scheme"`
-	EtcdKeyFile    string     `json:"etcd_key_file"`
-	EtcdCertFile   string     `json:"etcd_cert_file"`
-	EtcdCaCertFile string     `json:"etcd_ca_cert_file"`
+	MTU                 int        `json:"mtu"`
+	Hostname            string     `json:"hostname"`
+	Nodename            string     `json:"nodename"`
+	RequireNodenameFile bool       `json:"require_nodename_file"`
+	DatastoreType       string     `json:"datastore_type"`
+	EtcdAuthority       string     `json:"etcd_authority"`
+	EtcdEndpoints       string     `json:"etcd_endpoints"`
+	LogLevel            string     `json:"log_level"`
+	Policy              Policy     `json:"policy"`
+	Kubernetes          Kubernetes `json:"kubernetes"`
+	Args                Args       `json:"args"`
+	EtcdScheme          string     `json:"etcd_scheme"`
+	EtcdKeyFile         string     `json:"etcd_key_file"`
+	EtcdCertFile        string     `json:"etcd_cert_file"`
+	EtcdCaCertFile      string     `json:"etcd_ca_cert_file"`
 }
 
-// CNITestArgs is the CNI_ARGS used for test purpose.
+// CNITestArgs is the CNI_ARGS used for test purposes.
 type CNITestArgs struct {
 	types.CommonArgs
 	CNI_TEST_NAMESPACE types.UnmarshallableString

diff --git a/utils/utils.go b/utils/utils.go
@@ -18,6 +18,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"net"
 	"os"
 	"regexp"
@@ -57,12 +58,34 @@ func DetermineNodename(conf types.NetConf) string {
 		nodename = conf.Hostname
 		logrus.Warn("Configuration option 'hostname' is deprecated, use 'nodename' instead.")
 	}
+	if nff := nodenameFromFile(); nff != "" {
+		logrus.Debugf("Read node name from file: %s", nff)
+		nodename = nff
+	}
 	if conf.Nodename != "" {
+		logrus.Debugf("Read node name from CNI conf: %s", conf.Nodename)
 		nodename = conf.Nodename
 	}
+	logrus.Debugf("Using node name %s", nodename)
 	return nodename
 }
 
+// nodenameFromFile reads the /var/lib/calico/nodename file if it exists and
+// returns the nodename within.
+func nodenameFromFile() string {
+	data, err := ioutil.ReadFile("/var/lib/calico/nodename")
+	if err != nil {
+		if strings.Contains(fmt.Sprintf("%s", err), "no such file") {
+			// File doesn't exist, return empty string.
+			logrus.Debug("File does not exist: /var/lib/calico/nodename")
+			return ""
+		}
+		logrus.WithError(err).Error("Failed to read /var/lib/calico/nodename")
+		return ""
+	}
+	return string(data)
+}
+
 // CreateOrUpdate creates the WorkloadEndpoint if ResourceVersion is not specified,
 // or Update if it's specified.
 func CreateOrUpdate(ctx context.Context, client client.Interface, wep *api.WorkloadEndpoint) (*api.WorkloadEndpoint, error) {