| |
| In addition to using normal file images for the emulated storage |
| devices, QEMU can also use networked resources such as iSCSI devices. |
| These are specified using a special URL syntax. |
| |
| ``iSCSI`` |
| iSCSI support allows QEMU to access iSCSI resources directly and use |
| as images for the guest storage. Both disk and cdrom images are |
| supported. |
| |
| Syntax for specifying iSCSI LUNs is |
| "iscsi://<target-ip>[:<port>]/<target-iqn>/<lun>" |
| |
| By default qemu will use the iSCSI initiator-name |
| 'iqn.2008-11.org.linux-kvm[:<name>]' but this can also be set from |
| the command line or a configuration file. |
| |
| Since version QEMU 2.4 it is possible to specify a iSCSI request |
| timeout to detect stalled requests and force a reestablishment of the |
| session. The timeout is specified in seconds. The default is 0 which |
| means no timeout. Libiscsi 1.15.0 or greater is required for this |
| feature. |
| |
| Example (without authentication): |
| |
| .. parsed-literal:: |
| |
| |qemu_system| -iscsi initiator-name=iqn.2001-04.com.example:my-initiator \\ |
| -cdrom iscsi://192.0.2.1/iqn.2001-04.com.example/2 \\ |
| -drive file=iscsi://192.0.2.1/iqn.2001-04.com.example/1 |
| |
| Example (CHAP username/password via URL): |
| |
| .. parsed-literal:: |
| |
| |qemu_system| -drive file=iscsi://user%password@192.0.2.1/iqn.2001-04.com.example/1 |
| |
| Example (CHAP username/password via environment variables): |
| |
| .. parsed-literal:: |
| |
| LIBISCSI_CHAP_USERNAME="user" \\ |
| LIBISCSI_CHAP_PASSWORD="password" \\ |
| |qemu_system| -drive file=iscsi://192.0.2.1/iqn.2001-04.com.example/1 |
| |
| ``NBD`` |
| QEMU supports NBD (Network Block Devices) both using TCP protocol as |
| well as Unix Domain Sockets. With TCP, the default port is 10809. |
| |
| Syntax for specifying a NBD device using TCP, in preferred URI form: |
| "nbd://<server-ip>[:<port>]/[<export>]" |
| |
| Syntax for specifying a NBD device using Unix Domain Sockets; |
| remember that '?' is a shell glob character and may need quoting: |
| "nbd+unix:///[<export>]?socket=<domain-socket>" |
| |
| Older syntax that is also recognized: |
| "nbd:<server-ip>:<port>[:exportname=<export>]" |
| |
| Syntax for specifying a NBD device using Unix Domain Sockets |
| "nbd:unix:<domain-socket>[:exportname=<export>]" |
| |
| Example for TCP |
| |
| .. parsed-literal:: |
| |
| |qemu_system| --drive file=nbd:192.0.2.1:30000 |
| |
| Example for Unix Domain Sockets |
| |
| .. parsed-literal:: |
| |
| |qemu_system| --drive file=nbd:unix:/tmp/nbd-socket |
| |
| ``SSH`` |
| QEMU supports SSH (Secure Shell) access to remote disks. |
| |
| Examples: |
| |
| .. parsed-literal:: |
| |
| |qemu_system| -drive file=ssh://user@host/path/to/disk.img |
| |qemu_system| -drive file.driver=ssh,file.user=user,file.host=host,file.port=22,file.path=/path/to/disk.img |
| |
| Currently authentication must be done using ssh-agent. Other |
| authentication methods may be supported in future. |
| |
| ``GlusterFS`` |
| GlusterFS is a user space distributed file system. QEMU supports the |
| use of GlusterFS volumes for hosting VM disk images using TCP, Unix |
| Domain Sockets and RDMA transport protocols. |
| |
| Syntax for specifying a VM disk image on GlusterFS volume is |
| |
| .. parsed-literal:: |
| |
| URI: |
| gluster[+type]://[host[:port]]/volume/path[?socket=...][,debug=N][,logfile=...] |
| |
| JSON: |
| 'json:{"driver":"qcow2","file":{"driver":"gluster","volume":"testvol","path":"a.img","debug":N,"logfile":"...", |
| "server":[{"type":"tcp","host":"...","port":"..."}, |
| {"type":"unix","socket":"..."}]}}' |
| |
| Example |
| |
| .. parsed-literal:: |
| |
| URI: |
| |qemu_system| --drive file=gluster://192.0.2.1/testvol/a.img, |
| file.debug=9,file.logfile=/var/log/qemu-gluster.log |
| |
| JSON: |
| |qemu_system| 'json:{"driver":"qcow2", |
| "file":{"driver":"gluster", |
| "volume":"testvol","path":"a.img", |
| "debug":9,"logfile":"/var/log/qemu-gluster.log", |
| "server":[{"type":"tcp","host":"1.2.3.4","port":24007}, |
| {"type":"unix","socket":"/var/run/glusterd.socket"}]}}' |
| |qemu_system| -drive driver=qcow2,file.driver=gluster,file.volume=testvol,file.path=/path/a.img, |
| file.debug=9,file.logfile=/var/log/qemu-gluster.log, |
| file.server.0.type=tcp,file.server.0.host=1.2.3.4,file.server.0.port=24007, |
| file.server.1.type=unix,file.server.1.socket=/var/run/glusterd.socket |
| |
| See also http://www.gluster.org. |
| |
| ``HTTP/HTTPS/FTP/FTPS`` |
| QEMU supports read-only access to files accessed over http(s) and |
| ftp(s). |
| |
| Syntax using a single filename: |
| |
| :: |
| |
| <protocol>://[<username>[:<password>]@]<host>/<path> |
| |
| where: |
| |
| ``protocol`` |
| 'http', 'https', 'ftp', or 'ftps'. |
| |
| ``username`` |
| Optional username for authentication to the remote server. |
| |
| ``password`` |
| Optional password for authentication to the remote server. |
| |
| ``host`` |
| Address of the remote server. |
| |
| ``path`` |
| Path on the remote server, including any query string. |
| |
| The following options are also supported: |
| |
| ``url`` |
| The full URL when passing options to the driver explicitly. |
| |
| ``readahead`` |
| The amount of data to read ahead with each range request to the |
| remote server. This value may optionally have the suffix 'T', 'G', |
| 'M', 'K', 'k' or 'b'. If it does not have a suffix, it will be |
| assumed to be in bytes. The value must be a multiple of 512 bytes. |
| It defaults to 256k. |
| |
| ``sslverify`` |
| Whether to verify the remote server's certificate when connecting |
| over SSL. It can have the value 'on' or 'off'. It defaults to |
| 'on'. |
| |
| ``cookie`` |
| Send this cookie (it can also be a list of cookies separated by |
| ';') with each outgoing request. Only supported when using |
| protocols such as HTTP which support cookies, otherwise ignored. |
| |
| ``timeout`` |
| Set the timeout in seconds of the CURL connection. This timeout is |
| the time that CURL waits for a response from the remote server to |
| get the size of the image to be downloaded. If not set, the |
| default timeout of 5 seconds is used. |
| |
| Note that when passing options to qemu explicitly, ``driver`` is the |
| value of <protocol>. |
| |
| Example: boot from a remote Fedora 20 live ISO image |
| |
| .. parsed-literal:: |
| |
| |qemu_system_x86| --drive media=cdrom,file=https://archives.fedoraproject.org/pub/archive/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso,readonly |
| |
| |qemu_system_x86| --drive media=cdrom,file.driver=http,file.url=http://archives.fedoraproject.org/pub/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso,readonly |
| |
| Example: boot from a remote Fedora 20 cloud image using a local |
| overlay for writes, copy-on-read, and a readahead of 64k |
| |
| .. parsed-literal:: |
| |
| qemu-img create -f qcow2 -o backing_file='json:{"file.driver":"http",, "file.url":"http://archives.fedoraproject.org/pub/archive/fedora/linux/releases/20/Images/x86_64/Fedora-x86_64-20-20131211.1-sda.qcow2",, "file.readahead":"64k"}' /tmp/Fedora-x86_64-20-20131211.1-sda.qcow2 |
| |
| |qemu_system_x86| -drive file=/tmp/Fedora-x86_64-20-20131211.1-sda.qcow2,copy-on-read=on |
| |
| Example: boot from an image stored on a VMware vSphere server with a |
| self-signed certificate using a local overlay for writes, a readahead |
| of 64k and a timeout of 10 seconds. |
| |
| .. parsed-literal:: |
| |
| qemu-img create -f qcow2 -o backing_file='json:{"file.driver":"https",, "file.url":"https://user:password@vsphere.example.com/folder/test/test-flat.vmdk?dcPath=Datacenter&dsName=datastore1",, "file.sslverify":"off",, "file.readahead":"64k",, "file.timeout":10}' /tmp/test.qcow2 |
| |
| |qemu_system_x86| -drive file=/tmp/test.qcow2 |
