retry on 'unexpected EOF' error

'unexpected EOF' is usually a transient error. client-go request
uses IsProbableEOF to determine whether it is going to retry a
failed request.

staging/src/k8s.io/apimachinery/pkg/util/net/http.go

@@ -83,6 +83,8 @@ func IsProbableEOF(err error) bool {
 	switch {
 	case err == io.EOF:
 		return true
+	case err == io.ErrUnexpectedEOF:
+		return true
 	case msg == "http: can't write HTTP request on broken connection":
 		return true
 	case strings.Contains(msg, "http2: server sent GOAWAY and closed the connection"):

staging/src/k8s.io/apimachinery/pkg/util/net/http_test.go

@@ -23,6 +23,7 @@ import (
 	"bytes"
 	"crypto/tls"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
 	"net/http"
@@ -1008,3 +1009,65 @@ func TestParseWarningHeaders(t *testing.T) {
 		})
 	}
 }
+
+func TestIsProbableEOF(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      error
+		expected bool
+	}{
+		{
+			name:     "with no error",
+			expected: false,
+		},
+		{
+			name:     "with EOF error",
+			err:      io.EOF,
+			expected: true,
+		},
+		{
+			name:     "with unexpected EOF error",
+			err:      io.ErrUnexpectedEOF,
+			expected: true,
+		},
+		{
+			name:     "with broken connection error",
+			err:      fmt.Errorf("http: can't write HTTP request on broken connection"),
+			expected: true,
+		},
+		{
+			name:     "with server sent GOAWAY error",
+			err:      fmt.Errorf("error foo - http2: server sent GOAWAY and closed the connection - error bar"),
+			expected: true,
+		},
+		{
+			name:     "with connection reset by peer error",
+			err:      fmt.Errorf("error foo - connection reset by peer - error bar"),
+			expected: true,
+		},
+		{
+			name:     "with use of closed network connection error",
+			err:      fmt.Errorf("error foo - Use of closed network connection - error bar"),
+			expected: true,
+		},
+		{
+			name: "with url error",
+			err: &url.Error{
+				Err: io.ErrUnexpectedEOF,
+			},
+			expected: true,
+		},
+		{
+			name:     "with unrecognized error",
+			err:      fmt.Errorf("error foo"),
+			expected: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			actual := IsProbableEOF(test.err)
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+}