consider:
* You can only run Linux based OS inside containers, i.e. it is not
- possible to run Free BSD or MS Windows inside.
+ possible to run FreeBSD or MS Windows inside.
-* For security reasons, access to host resources need to be
+* For security reasons, access to host resources needs to be
restricted. This is done with AppArmor, SecComp filters and other
- kernel feature. Be prepared that some syscalls are not allowed
+ kernel features. Be prepared that some syscalls are not allowed
inside containers.
{pve} uses https://linuxcontainers.org/[LXC] as underlying container
technology. We consider LXC as low-level library, which provides
-countless options. It would be to difficult to use those tools
+countless options. It would be too difficult to use those tools
directly. Instead, we provide a small wrapper called `pct`, the
"Proxmox Container Toolkit".
-The toolkit it tightly coupled with {pve}. That means that it is aware
+The toolkit is tightly coupled with {pve}. That means that it is aware
of the cluster setup, and it can use the same network and storage
resources as fully virtualized VMs. You can even use the {pve}
firewall, or manage containers using the HA framework.
Containers use the same kernel as the host, so there is a big attack
surface for malicious users. You should consider this fact if you
provide containers to totally untrusted people. In general, fully
-virtualized VM provides better isolation.
+virtualized VMs provide better isolation.
The good news is that LXC uses many kernel security features like
AppArmor, CGroups and PID and user namespaces, which makes containers
Unprivileged containers
~~~~~~~~~~~~~~~~~~~~~~~
-This kind of containers use a new kernel feature, called user
+This kind of containers use a new kernel feature called user
namespaces. The root uid 0 inside the container is mapped to an
unprivileged user outside the container. This means that most security
issues (container escape, resource abuse, ...) in those containers
will affect a random unprivileged user, and so would be a generic
-kernel security bug rather than a LXC issue. LXC people think
+kernel security bug rather than an LXC issue. The LXC team thinks
unprivileged containers are safe by design.
Configuration
-------------
-The '/etc/pve/lxc/<CTID>.conf' files stores container configuration,
-where '<CTID>' is the numeric ID of the given container. Note that
-CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
-cluster wide unique. Files are stored inside '/etc/pve/', so they get
-automatically replicated to all other cluster nodes.
+The '/etc/pve/lxc/<CTID>.conf' file stores container configuration,
+where '<CTID>' is the numeric ID of the given container. Like all
+other files stored inside '/etc/pve/', they get automatically
+replicated to all other cluster nodes.
+
+NOTE: CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
+unique cluster wide.
.Example Container Configuration
----
...
----
-There are a view snapshot related properties like 'parent' and
-'snaptime'. They 'parent' property is used to store the parent/child
+There are a few snapshot related properties like 'parent' and
+'snaptime'. The 'parent' property is used to store the parent/child
relationship between snapshots. 'snaptime' is the snapshot creation
time stamp (unix epoch).
set /etc/hostname:: to set the container name
-modify /etc/hosts:: allow to lookup the local hostname
+modify /etc/hosts:: to allow lookup of the local hostname
network setup:: pass the complete network setup to the container
configure DNS:: pass information about DNS servers
-adopt the init system:: for example, fix the number os spawned getty processes
+adapt the init system:: for example, fix the number of spawned getty processes
set the root password:: when creating a new container
rewrite ssh_host_keys:: so that each container has unique keys
-randomize crontab:: so that cron does not start at same time on all containers
+randomize crontab:: so that cron does not start at the same time on all containers
+
+Changes made by {PVE} are enclosed by comment markers:
+
+----
+# --- BEGIN PVE ---
+<data>
+# --- END PVE ---
+----
+
+Those markers will be inserted at a reasonable location in the
+file. If such a section already exists, it will be updated in place
+and will not be moved.
+
+Modification of a file can be prevented by adding a `.pve-ignore.`
+file for it. For instance, if the file `/etc/.pve-ignore.hosts`
+exists then the `/etc/hosts` file will not be touched. This can be a
+simple empty file creatd via:
+
+ # touch /etc/.pve-ignore.hosts
-Above task depends on the OS type, so the implementation is different
-for each OS type. You can also disable any modifications by manually
-setting the 'ostype' to 'unmanaged'.
+Most modifications are OS dependent, so they differ between different
+distributions and versions. You can completely disable modifications
+by manually setting the 'ostype' to 'unmanaged'.
OS type detection is done by testing for certain files inside the
container:
Alpine:: test /etc/alpine-release
-NOTE: Container start fails is configured 'ostype' differs from auto
+NOTE: Container start fails if the configured 'ostype' differs from the auto
detected type.
+Options
+~~~~~~~
+
+include::pct.conf.5-opts.adoc[]
+
+
+Container Images
+----------------
+
+Container Images, sometimes also referred to as "templates" or
+"appliances", are 'tar' archives which contain everything to run a
+container. You can think of it as a tidy container backup. Like most
+modern container toolkits, 'pct' uses those images when you create a
+new container, for example:
+
+ pct create 999 local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz
+
+Proxmox itself ships a set of basic templates for most common
+operating systems, and you can download them using the 'pveam' (short
+for {pve} Appliance Manager) command line utility. You can also
+download https://www.turnkeylinux.org/[TurnKey Linux] containers using
+that tool (or the graphical user interface).
+
+Our image repositories contain a list of available images, and there
+is a cron job run each day to download that list. You can trigger that
+update manually with:
+
+ pveam update
+
+After that you can view the list of available images using:
+
+ pveam available
+
+You can restrict this large list by specifying the 'section' you are
+interested in, for example basic 'system' images:
+
+.List available system images
+----
+# pveam available --section system
+system archlinux-base_2015-24-29-1_x86_64.tar.gz
+system centos-7-default_20160205_amd64.tar.xz
+system debian-6.0-standard_6.0-7_amd64.tar.gz
+system debian-7.0-standard_7.0-3_amd64.tar.gz
+system debian-8.0-standard_8.0-1_amd64.tar.gz
+system ubuntu-12.04-standard_12.04-1_amd64.tar.gz
+system ubuntu-14.04-standard_14.04-1_amd64.tar.gz
+system ubuntu-15.04-standard_15.04-1_amd64.tar.gz
+system ubuntu-15.10-standard_15.10-1_amd64.tar.gz
+----
+
+Before you can use such a template, you need to download them into one
+of your storages. You can simply use storage 'local' for that
+purpose. For clustered installations, it is preferred to use a shared
+storage so that all nodes can access those images.
+
+ pveam download local debian-8.0-standard_8.0-1_amd64.tar.gz
+
+You are now ready to create containers using that image, and you can
+list all downloaded images on storage 'local' with:
+
+----
+# pveam list local
+local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz 190.20MB
+----
+
+The above command shows you the full {pve} volume identifiers. They include
+the storage name, and most other {pve} commands can use them. For
+examply you can delete that image later with:
+
+ pveam remove local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz
+
+
Container Storage
-----------------
a single mount point, the root file system. This was further
restricted to specific file system types like 'ext4' and 'nfs'.
Additional mounts are often done by user provided scripts. This turend
-out to be complex and error prone, so we trie to avoid that now.
+out to be complex and error prone, so we try to avoid that now.
Our new LXC based container model is more flexible regarding
storage. First, you can have more than a single mount point. This
The second big improvement is that you can use any storage type
supported by the {pve} storage library. That means that you can store
your containers on local 'lvmthin' or 'zfs', shared 'iSCSI' storage,
-or even on distributed storage systems like 'ceph'. And it enables us
+or even on distributed storage systems like 'ceph'. It also enables us
to use advanced storage features like snapshots and clones. 'vzdump'
-can also use the snapshots feature to provide consistent container
+can also use the snapshot feature to provide consistent container
backups.
Last but not least, you can also mount local devices directly, or
mount local directories using bind mounts. That way you can access
local storage inside containers with zero overhead. Such bind mounts
-also provides an easy way to share data between different containers.
+also provide an easy way to share data between different containers.
+
+
+Mount Points
+~~~~~~~~~~~~
+
+Beside the root directory the container can also have additional mount points.
+Currently there are basically three types of mount points: storage backed
+mount points, bind mounts and device mounts.
+
+Storage backed mount points are managed by the {pve} storage subsystem and come
+in three different flavors:
+
+- Image based: These are raw images containing a single ext4 formatted file
+ system.
+- ZFS Subvolumes: These are technically bind mounts, but with managed storage,
+ and thus allow resizing and snapshotting.
+- Directories: passing `size=0` triggers a special case where instead of a raw
+ image a directory is created.
+
+Bind mounts are considered to not be managed by the storage subsystem, so you
+cannot make snapshots or deal with quotas from inside the container, and with
+unprivileged containers you might run into permission problems caused by the
+user mapping, and cannot use ACLs from inside an unprivileged container.
+
+Similarly device mounts are not managed by the storage, but for these the
+`quota` and `acl` options will be honored.
+
+WARNING: Because of existing issues in the Linux kernel's freezer
+subsystem the usage of FUSE mounts inside a container is strongly
+advised against, as containers need to be frozen for suspend or
+snapshot mode backups. If FUSE mounts cannot be replaced by other
+mounting mechanisms or storage technologies, it is possible to
+establish the FUSE mount on the Proxmox host and use a bind
+mount point to make it accessible inside the container.
+
+WARNING: For security reasons, bind mounts should only be established
+using source directories especially reserved for this purpose, e.g., a
+directory hierarchy under `/mnt/bindmounts`. Never bind mount system
+directories like `/`, `/var` or `/etc` into a container - this poses a
+great security risk. The bind mount source path must not contain any symlinks.
+
+The root mount point is configured with the 'rootfs' property, and you can
+configure up to 10 additional mount points. The corresponding options
+are called 'mp0' to 'mp9', and they can contain the following setting:
+
+include::pct-mountpoint-opts.adoc[]
+
+.Typical Container 'rootfs' configuration
+----
+rootfs: thin1:base-100-disk-1,size=8G
+----
+
+Using quotas inside containers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Quotas allow to set limits inside a container for the amount of disk
+space that each user can use. This only works on ext4 image based
+storage types and currently does not work with unprivileged
+containers.
+
+Activating the `quota` option causes the following mount options to be
+used for a mount point:
+`usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0`
+
+This allows quotas to be used like you would on any other system. You
+can initialize the `/aquota.user` and `/aquota.group` files by running
+
+----
+quotacheck -cmug /
+quotaon /
+----
+
+and edit the quotas via the `edquota` command. Refer to the documentation
+of the distribution running inside the container for details.
+
+NOTE: You need to run the above commands for every mount point by passing
+the mount point's path instead of just `/`.
+
+
+Using ACLs inside containers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The standard Posix Access Control Lists are also available inside containers.
+ACLs allow you to set more detailed file ownership than the traditional user/
+group/others model.
+
+
+Container Network
+-----------------
+
+You can configure up to 10 network interfaces for a single
+container. The corresponding options are called 'net0' to 'net9', and
+they can contain the following setting:
+
+include::pct-network-opts.adoc[]
Managing Containers with 'pct'
'pct' is the tool to manage Linux Containers on {pve}. You can create
and destroy containers, and control execution (start, stop, migrate,
...). You can use pct to set parameters in the associated config file,
-like network configuration or memory.
+like network configuration or memory limits.
CLI Usage Examples
-------------------
+~~~~~~~~~~~~~~~~~~
-Create a container based on a Debian template (provided you downloaded
-the template via the webgui before)
+Create a container based on a Debian template (provided you have
+already downloaded the template via the webgui)
pct create 100 /var/lib/vz/template/cache/debian-8.0-standard_8.0-1_amd64.tar.gz
Reduce the memory of the container to 512MB
- pct set -memory 512 100
+ pct set 100 -memory 512
+
Files
------
- CRIU: for live migration (planned)
-- We use latest available kernels (4.2.X)
+- We use latest available kernels (4.4.X)
-- image based deployment (templates)
+- Image based deployment (templates)
- Container setup from host (Network, DNS, Storage, ...)
projects / pve-docs.git / blobdiff