Using per-node configuration

In order to use per-node configuration, you need to create Virtlet CRD definitions before you deploy Virtlet:

virtletctl gen --crd | kubectl apply -f -

After that, you can add one or more Virtlet configuration mappings:

kubectl apply -f - <<EOF
---
apiVersion: "virtlet.k8s/v1"
kind: VirtletConfigMapping
metadata:
  name: test
  namespace: kube-system
spec:
  nodeName: kube-node-2
  priority: 1
  config:
    disableKVM: true
    logLevel: 5
    rawDevices: sda*,loop*
---
apiVersion: "virtlet.k8s/v1"
kind: VirtletConfigMapping
metadata:
  name: test-labels
  namespace: kube-system
spec:
  nodeSelector:
    foo: bar
  priority: 10
  config:
    logLevel: 3
EOF

You can delete Virtlet pods to have them restarted and pick up the changes after you add, remove or modify the configuration mappings.

All the config mappings must reside in kube-system namespace. Each mapping can specify nodeSelector or nodeName to target a subset of the nodes. If neither nodeSelector nor nodeName is specified, the mapping will target all the nodes. If the several mappings apply to the node, their order is determined by priority value, with mappings with higher value of priority taking precendence. config specifies the list of configuration fields (see the full table of config fields in the next section of this document).

In the example above, for the node named kube-node-2, KVM is disabled, log level is set to 5 and the raw device list is set to sda*,loop*. For nodes with foo=bar label, the log level is overridden and set to 3. If kube-node-2 node has foo=bar label, the log level will be set to 3 there as the label-based mapping has higher priority.

Configuration options summary

The table below lists all the Virtlet configuration fields, with their corresponding command line flags and environment variables that are handled by Virtlet binary. Note that you may only need these environment variables and configuration flags if you're not using the standard Virtlet deployment YAML as generated by virtletctl gen.

Description	Config field	Default value	Type	Command line flag / Env
Path to fd server socket	fdServerSocketPath	/var/lib/virtlet/tapfdserver.sock	string	--fd-server-socket-path / VIRTLET_FD_SERVER_SOCKET_PATH
Path to the virtlet database	databasePath	/var/lib/virtlet/virtlet.db	string	--database-path / VIRTLET_DATABASE_PATH
Image download protocol. Can be https or http	downloadProtocol	https	string	--image-download-protocol / VIRTLET_DOWNLOAD_PROTOCOL
Image directory	imageDir	/var/lib/virtlet/images	string	--image-dir / VIRTLET_IMAGE_DIR
Image name translation configs directory	imageTranslationConfigsDir	/etc/virtlet/images	string	--image-translation-configs-dir / VIRTLET_IMAGE_TRANSLATIONS_DIR
Libvirt connection URI	libvirtURI	qemu:///system	string	--libvirt-uri / VIRTLET_LIBVIRT_URI
Comma separated list of raw device glob patterns which VMs can access (without '/dev/' prefix)	rawDevices	loop*	string	--raw-devices / VIRTLET_RAW_DEVICES
The path to UNIX domain socket for CRI service to listen on	criSocketPath	/run/virtlet.sock	string	--listen / VIRTLET_CRI_SOCKET_PATH
Display logging and the streamer	disableLogging	false	boolean	--disable-logging / VIRTLET_DISABLE_LOGGING
Forcibly disable KVM support	disableKVM	false	boolean	--disable-kvm / VIRTLET_DISABLE_KVM
Enable SR-IOV support	enableSriov	false	boolean	--enable-sriov / VIRTLET_SRIOV_SUPPORT
Path to CNI plugin binaries	cniPluginDir	/opt/cni/bin	string	--cni-bin-dir / VIRTLET_CNI_PLUGIN_DIR
Path to the CNI configuration directory	cniConfigDir	/etc/cni/net.d	string	--cni-conf-dir / VIRTLET_CNI_CONFIG_DIR
Calico subnet size to use	calicoSubnetSize	24	integer	--calico-subnet-size / VIRTLET_CALICO_SUBNET
Enable regexp image name translation	enableRegexpImageTranslation	true	boolean	--enable-regexp-image-translation / IMAGE_REGEXP_TRANSLATION
CPU model to use in libvirt domain definition (libvirt's default value will be used if not set)	cpuModel		string	--cpu-model / VIRTLET_CPU_MODEL
configurable port to the virtlet server	streamPort	10010	integer	--stream-port / VIRTLET_STREAM_PORT
Pod's root dir in kubelet	kubeletRootDir	/var/lib/kubelet/pods	string	--kubelet-root-dir / KUBELET_ROOT_DIR
Log level to use	logLevel	1	integer	--v / VIRTLET_LOGLEVEL

Only the following config fields mentioned in this table can be used with standard Virtlet deployment YAML: downloadProtocol, rawDevices, disableKVM, enableSriov, calicoSubnetSize, enableRegexpImageTranslation, cpuModel and logLevel. Other options may need adjusting the YAML to change the paths of volume mounts. disableLogging option is intended for debugging purposes only.