Skip to content

Latest commit

 

History

History
303 lines (222 loc) · 11.2 KB

README.windows.rst

File metadata and controls

303 lines (222 loc) · 11.2 KB
Raw

About

Ceph Windows support is currently a work in progress. For now, the main focus is the client side, allowing Windows hosts to consume rados, rbd and cephfs resources.

Building

At the moment, mingw gcc >= 8 is the only supported compiler for building ceph components for Windows. Support for msvc and clang will be added soon.

win32_build.sh can be used for cross compiling Ceph and its dependencies. It may be called from a Linux environment, including Windows Subsystem for Linux. MSYS2 and CygWin may also work but those weren't tested.

The script accepts the following flags:

Flag Description Default value
CEPH_DIR The Ceph source code directory. The same as the script.
BUILD_DIR The directory where the generated artifacts will be placed. $CEPH_DIR/build
DEPS_DIR The directory where the Ceph dependencies will be built. $CEPH_DIR/build.deps
NUM_WORKERS The number of workers to use when building Ceph. The number of vcpus available
CLEAN_BUILD Clean the build directory.  
SKIP_BUILD Run cmake without actually performing the build.  

Current status

The rados and rbd binaries and libs compile successfully and can be used on Windows, successfully connecting to the cluster and consuming pools.

Ceph filesystems can be mounted using the ceph-dokan command, which requires the Dokany package to be installed. Note that dokany is a well maintained fork of the Dokan project, allowing filesystems to be implemented in userspace, pretty much like Fuse.

RBD images can be mounted using the rbd or rbd-wnbd commands. The WNBD driver is required for mapping RBD images on Windows.

The libraries have to be built statically at the moment. The reason is that there are a few circular library dependencies or unspecified dependencies, which isn't supported when building DLLs. This mostly affects cls libraries.

A significant number of tests from the tests directory have been ported, providing adequate coverage.

Supported platforms

Windows Server 2019 and Windows Server 2016 are supported. Previous Windows Server versions, including Windows client versions such as Windows 10, might work but haven't been tested.

Windows Server 2016 does not provide unix sockets, in which case the Ceph admin socket feature will be unavailable.

Compatibility

RBD images can be exposed to the OS and host Windows partitions or they can be attached to Hyper-V VMs in the same way as iSCSI disks.

At the moment, the Microsoft Failover Cluster can't use WNBD disks as Cluster Shared Volumes (CSVs) underlying storage. The main reason is that WNBD and rbd-wnbd don't support the SCSI Persistent Reservations feature yet.

OpenStack integration has been proposed as well and will most probably be included in the next OpenStack release, allowing RBD images managed by OpenStack Cinder to be attached to Hyper-V VMs managed by OpenStack Nova.

Installing

Soon we're going to provide an MSI installed for Ceph. For now, unzip the binaries that you may have obtained by following the building step.

You may want to update the environment PATH variable, including the Ceph path. Assuming that you've copied the Ceph binaries to C:\Ceph, you may use the following Powershell command:

[Environment]::SetEnvironmentVariable("Path", "$env:PATH;C:\ceph", "Machine")

In order to mount Ceph filesystems, you will have to install Dokany. You may fetch the installer as well as the source code from the Dokany Github repository: https://github.com/dokan-dev/dokany/releases

Make sure to use 1.3.1, which at time of the writing is the latest stable release.

In order to map RBD images, the WNBD driver must be installed. Please check out this page for more details about WNBD and the install process: https://github.com/cloudbase/wnbd

Configuring

ceph.conf

The default location for the ceph.conf file on Windows is %ProgramData%\ceph\ceph.conf, which usually expands to C:\ProgramData\ceph\ceph.conf.

Below you may find a sample. Please fill in the monitor addresses accordingly.

[global]
    log to stderr = true

    run dir = C:/ProgramData/ceph/out
    crash dir = C:/ProgramData/ceph/out
[client]
    keyring = C:/ProgramData/ceph/keyring
    ; log file = C:/ProgramData/ceph/out/$name.$pid.log
    admin socket = C:/ProgramData/ceph/out/$name.$pid.asok
[global]
    mon host =  [v2:xx.xx.xx.xx:40623,v1:xx.xx.xx.xx:40624] [v2:xx.xx.xx.xx:40625,v1:xx.xx.xx.xx:40626] [v2:xx.xx.xx.xx:40627,v1:xx.xx.xx.xx:40628]

Assuming that you're going to use this config sample, don't forget to also copy your keyring file to the specified location and make sure that the configured directories exist (e.g. C:\ProgramData\ceph\out).

Please use slashes / instead of backslashes \ as path separators within ceph.conf for the time being. Also, don't forget to include a newline at the end of the file, Ceph will complain otherwise.

Windows service

In order to ensure that rbd-wnbd mappings survive host reboot, you'll have to configure it to run as a Windows service. Only one such service may run per host.

All mappings are currently persistent, being recreated when the service starts, unless explicitly unmapped. The service disconnects the mappings when being stopped. This also allows adjusting the Windows service start order so that rbd images can be mapped before starting services that may depend on it, such as VMMS.

In order to be able to reconnect the images, rbd-wnbd stores mapping information in the Windows registry at the following location: SYSTEM\CurrentControlSet\Services\rbd-wnbd.

The following command can be used to configure the service. Please update the rbd-wnbd.exe path accordingly.

New-Service -Name "ceph-rbd" `
            -Description "Ceph RBD Mapping Service" `
            -BinaryPathName "c:\ceph\rbd-wnbd.exe service" `
            -StartupType Automatic

Usage

Cephfs

In order to mount a ceph filesystem, the following command can be used:

ceph-dokan.exe -c c:\ceph.conf -l x

The above command will mount the default ceph filesystem using the drive letter x. If ceph.conf is placed at the default location, which is %ProgramData%\ceph\ceph.conf, then this argument becomes optional.

The -l argument also allows using an empty folder as a mountpoint instead of a drive letter.

The uid and gid used for mounting the filesystem defaults to 0 and may be changed using the -u and -g arguments. -n can be used in order to skip enforcing permissions on client side. Be aware that Windows ACLs are ignored. Posix ACLs are supported but cannot be modified using the current CLI. In the future, we may add some command actions to change file ownership or permissions.

For debugging purposes, -d and s might be used. The first one will enable debug output and the latter will enable stderr logging. By default, debug messages are sent to a connected debugger.

You may use --help to get the full list of available options. The current syntax is up for discussion and might change.

RBD

The rbd command can be used to create, remove, import, export, map or unmap images exactly like it would on Linux.

Mapping images

In order to map RBD images, please install WNBD, as mentioned by the installing guide.

The behavior and CLI is similar to the Linux counterpart, with a few notable differences:

  • device paths cannot be requested. The disk number and path will be picked by Windows. If a device path is provided by the used when mapping an image, it will be used as an identifier, which can also be used when unmapping the image.
  • the show command was added, which describes a specific mapping. This can be used for retrieving the disk path.
  • the service command was added, allowing rbd-wnbd to run as a Windows service. All mappings are currently perisistent, being recreated when the service stops, unless explicitly unmapped. The service disconnects the mappings when being stopped.
  • the list command also includes a status column.

The purpose of the service mode is to ensure that mappings survive reboots and that the Windows service start order can be adjusted so that rbd images can be mapped before starting services that may depend on it, such as VMMS.

Please follow the windows_service guide in order to configure the service.

The mapped images can either be consumed by the host directly or exposed to Hyper-V VMs.

Hyper-V VM disks

The following sample imports an RBD image and boots a Hyper-V VM using it.

# Feel free to use any other image. This one is convenient to use for
# testing purposes because it's very small (~15MB) and the login prompt
# prints the pre-configured password.
wget http://download.cirros-cloud.net/0.5.1/cirros-0.5.1-x86_64-disk.img `
     -OutFile cirros-0.5.1-x86_64-disk.img

# We'll need to make sure that the imported images are raw (so no qcow2 or vhdx).
# You may get qemu-img from https://cloudbase.it/qemu-img-windows/
# You can add the extracted location to $env:Path or update the path accordingly.
qemu-img convert -O raw cirros-0.5.1-x86_64-disk.img cirros-0.5.1-x86_64-disk.raw

rbd import cirros-0.5.1-x86_64-disk.raw
# Let's give it a hefty 100MB size.
rbd resize cirros-0.5.1-x86_64-disk.raw --size=100MB

rbd-wnbd map cirros-0.5.1-x86_64-disk.raw

# Let's have a look at the mappings.
rbd-wnbd list
Get-Disk

$mappingJson = rbd-wnbd show cirros-0.5.1-x86_64-disk.raw --format=json
$mappingJson = $mappingJson | ConvertFrom-Json

$diskNumber = $mappingJson.disk_number

New-VM -VMName BootFromRBD -MemoryStartupBytes 512MB
# The disk must be turned offline before it can be passed to Hyper-V VMs
Set-Disk -Number $diskNumber -IsOffline $true
Add-VMHardDiskDrive -VMName BootFromRBD -DiskNumber $diskNumber
Start-VM -VMName BootFromRBD
Windows partitions

The following sample creates an empty RBD image, attaches it to the host and initializes a partition.

rbd create blank_image --size=1G
rbd-wnbd map blank_image

$mappingJson = rbd-wnbd show blank_image --format=json
$mappingJson = $mappingJson | ConvertFrom-Json

$diskNumber = $mappingJson.disk_number

# The disk must be online before creating or accessing partitions.
Set-Disk -Number $diskNumber -IsOffline $false

# Initialize the disk, partition it and create a fileystem.
Get-Disk -Number $diskNumber | `
    Initialize-Disk -PassThru | `
    New-Partition -AssignDriveLetter -UseMaximumSize | `
    Format-Volume -Force -Confirm:$false