Set the Varnish server.identity from its Pod namespace and name.

This is to ensure matches against server.identity as part of the
sharding implementation. VCL backend names generated for Varnish
backends must match this pattern.

container/varnishd_exec.sh

@@ -5,6 +5,6 @@ set -u
 
 exec /usr/sbin/varnishd -F -a :${HTTP_PORT},${PROTO} -a k8s=:${READY_PORT} \
      -a k8s_offload=${OFFLOAD_PATH},PROXY,group=${GROUP},mode=0660         \
-     -a vk8s_cfg=:${CONFIG_PORT}                                           \
+     -a vk8s_cfg=:${CONFIG_PORT} -i vk8s_${POD_NAMESPACE}_${POD_NAME}      \
      -S ${SECRET_PATH}/${SECRET_FILE} -T 0.0.0.0:${ADMIN_PORT}             \
      -p vcl_path=/etc/varnish -I /etc/varnish/start.cli	-f '' "$@"