qm-cloud-init.adoc

   1 [[qm_cloud_init]]
   2 Cloud-Init Support
   3 ------------------
   4 ifdef::wiki[]
   5 :pve-toplevel:
   6 endif::wiki[]
   7
   8 https://cloudinit.readthedocs.io[Cloud-Init] is the de facto
   9 multi-distribution package that handles early initialization of a
  10 virtual machine instance. Using Cloud-Init, configuration of network
  11 devices and ssh keys on the hypervisor side is possible. When the VM
  12 starts for the first time, the Cloud-Init software inside the VM will
  13 apply those settings.
  14
  15 Many Linux distributions provide ready-to-use Cloud-Init images, mostly
  16 designed for 'OpenStack'. These images will also work with {pve}. While
  17 it may seem convenient to get such ready-to-use images, we usually
  18 recommended to prepare the images by yourself. The advantage is that you
  19 will know exactly what you have installed, and this helps you later to
  20 easily customize the image for your needs.
  21
  22 Once you have created such a Cloud-Init image we recommend to convert it
  23 into a VM template. From a VM template you can quickly create linked
  24 clones, so this is a fast method to roll out new VM instances. You just
  25 need to configure the network (and maybe the ssh keys) before you start
  26 the new VM.
  27
  28 We recommend using SSH key-based authentication to login to the VMs
  29 provisioned by Cloud-Init. It is also possible to set a password, but
  30 this is not as safe as using SSH key-based authentication because {pve}
  31 needs to store an encrypted version of that password inside the
  32 Cloud-Init data.
  33
  34 {pve} generates an ISO image to pass the Cloud-Init data to the VM. For
  35 that purpose, all Cloud-Init VMs need to have an assigned CD-ROM drive.
  36 Usually, a serial console should be added and used as a display. Many Cloud-Init
  37 images rely on this, it is a requirement for OpenStack. However, other images
  38 might have problems with this configuration. Switch back to the default display
  39 configuration if using a serial console doesn't work.
  40
  41
  42 Preparing Cloud-Init Templates
  43 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  44
  45 The first step is to prepare your VM. Basically you can use any VM.
  46 Simply install the Cloud-Init packages inside the VM that you want to
  47 prepare. On Debian/Ubuntu based systems this is as simple as:
  48
  49 ----
  50 apt-get install cloud-init
  51 ----
  52
  53 WARNING: This command is *not* intended to be executed on the {pve} host, but
  54 only inside the VM.
  55
  56 Already many distributions provide ready-to-use Cloud-Init images (provided
  57 as `.qcow2` files), so alternatively you can simply download and
  58 import such images. For the following example, we will use the cloud
  59 image provided by Ubuntu at https://cloud-images.ubuntu.com.
  60
  61 ----
  62 # download the image
  63 wget https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img
  64
  65 # create a new VM
  66 qm create 9000 --memory 2048 --net0 virtio,bridge=vmbr0
  67
  68 # import the downloaded disk to local-lvm storage
  69 qm importdisk 9000 bionic-server-cloudimg-amd64.img local-lvm
  70
  71 # finally attach the new disk to the VM as scsi drive
  72 qm set 9000 --scsihw virtio-scsi-pci --scsi0 local-lvm:vm-9000-disk-1
  73 ----
  74
  75 NOTE: Ubuntu Cloud-Init images require the `virtio-scsi-pci`
  76 controller type for SCSI drives.
  77
  78 .Add Cloud-Init CD-ROM drive
  79
  80 [thumbnail="screenshot/gui-cloudinit-hardware.png"]
  81
  82 The next step is to configure a CD-ROM drive, which will be used to pass
  83 the Cloud-Init data to the VM.
  84
  85 ----
  86 qm set 9000 --ide2 local-lvm:cloudinit
  87 ----
  88
  89 To be able to boot directly from the Cloud-Init image, set the
  90 `bootdisk` parameter to `scsi0`, and restrict BIOS to boot from disk
  91 only. This will speed up booting, because VM BIOS skips the testing for
  92 a bootable CD-ROM.
  93
  94 ----
  95 qm set 9000 --boot c --bootdisk scsi0
  96 ----
  97
  98 For many Cloud-Init images, it is required to configure a serial console and use
  99 it as a display. If the configuration doesn't work for a given image however,
 100 switch back to the default display instead.
 101
 102 ----
 103 qm set 9000 --serial0 socket --vga serial0
 104 ----
 105
 106 In a last step, it is helpful to convert the VM into a template. From
 107 this template you can then quickly create linked clones.
 108 The deployment from VM templates is much faster than creating a full
 109 clone (copy).
 110 ----
 111 qm template 9000
 112 ----
 113
 114
 115 Deploying Cloud-Init Templates
 116 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 117
 118 [thumbnail="screenshot/gui-cloudinit-config.png"]
 119
 120 You can easily deploy such a template by cloning:
 121
 122 ----
 123 qm clone 9000 123 --name ubuntu2
 124 ----
 125
 126 Then configure the SSH public key used for authentication, and configure
 127 the IP setup:
 128
 129 ----
 130 qm set 123 --sshkey ~/.ssh/id_rsa.pub
 131 qm set 123 --ipconfig0 ip=10.0.10.123/24,gw=10.0.10.1
 132 ----
 133
 134 You can also configure all the Cloud-Init options using a single command
 135 only. We have simply split the above example to separate the
 136 commands for reducing the line length. Also make sure to adopt the IP
 137 setup for your specific environment.
 138
 139
 140 Custom Cloud-Init Configuration
 141 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 142
 143 The Cloud-Init integration also allows custom config files to be used instead
 144 of the automatically generated configs. This is done via the `cicustom`
 145 option on the command line:
 146
 147 ----
 148 qm set 9000 --cicustom "user=<volume>,network=<volume>,meta=<volume>"
 149 ----
 150
 151 The custom config files have to be on a storage that supports snippets and have
 152 to be available on all nodes the VM is going to be migrated to. Otherwise the
 153 VM won't be able to start.
 154 For example:
 155
 156 ----
 157 qm set 9000 --cicustom "user=local:snippets/userconfig.yaml"
 158 ----
 159
 160 There are three kinds of configs for Cloud-Init. The first one is the `user`
 161 config as seen in the example above. The second is the `network` config and
 162 the third the `meta` config. They can all be specified together or mixed
 163 and matched however needed.
 164 The automatically generated config will be used for any that don't have a
 165 custom config file specified.
 166
 167 The generated config can be dumped to serve as a base for custom configs:
 168
 169 ----
 170 qm cloudinit dump 9000 user
 171 ----
 172
 173 The same command exists for `network` and `meta`.
 174
 175
 176 Cloud-Init specific Options
 177 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 178
 179 include::qm-cloud-init-opts.adoc[]
 180
 181
 182 ifdef::wiki[]
 183
 184 See Also
 185 ~~~~~~~~
 186
 187 * link:/wiki/Qemu/KVM_Virtual_Machines[Qemu/KVM Virtual Machines]
 188
 189 endif::wiki[]