Accepting request 563669 from home:jfehlig:branches:Virtualization

- Add a qemu hook script providing functionality similar to Xen's
  block-dmmd script
  suse-qemu-domain-hook.py
  FATE#324177

OBS-URL: https://build.opensuse.org/request/show/563669
OBS-URL: https://build.opensuse.org/package/show/Virtualization/libvirt?expand=0&rev=659

libvirt.changes

@@ -1,3 +1,11 @@
+-------------------------------------------------------------------
+Thu Jan 11 16:52:43 UTC 2018 - jfehlig@suse.com
+
+- Add a qemu hook script providing functionality similar to Xen's
+  block-dmmd script
+  suse-qemu-domain-hook.py
+  FATE#324177
+
 -------------------------------------------------------------------
 Wed Jan  3 10:46:26 UTC 2018 - cbosdonnat@suse.com
 

libvirt.spec

@@ -305,6 +305,7 @@ Source1:        %{name}-%{version}.tar.xz.asc
 Source2:        %{name}.keyring
 Source3:        libvirtd-relocation-server.fw
 Source4:        libvirt-supportconfig
+Source5:        suse-qemu-domain-hook.py
 Source99:       baselibs.conf
 Source100:      %{name}-rpmlintrc
 # Upstream patches
@@ -407,6 +408,15 @@ Server side daemon required to manage the virtualization capabilities
 of recent versions of Linux. Requires a hypervisor specific sub-RPM
 for specific drivers.
 
+%package daemon-hooks
+Summary:        Hook scripts for the libvirtd daemon
+Group:          Development/Libraries/C and C++
+
+Requires:       %{name}-daemon = %{version}-%{release}
+
+%description daemon-hooks
+Default hook scripts for the libvirt daemon
+
 %package daemon-config-network
 Summary:        Default configuration files for the libvirtd daemon
 Group:          Development/Libraries/C and C++
@@ -1233,6 +1243,9 @@ install -m 644 %{S:3} %{buildroot}/%{_fwdefdir}/libvirtd-relocation-server
 mkdir -p %{buildroot}/usr/lib/supportconfig/plugins
 install -m 755 %{S:4} %{buildroot}/usr/lib/supportconfig/plugins/libvirt
 
+# install qemu hook script
+install -m 755 %{S:5} %{buildroot}/%{_sysconfdir}/libvirt/hooks/qemu
+
 %ifarch %{power64} s390x x86_64
 mv %{buildroot}/%{_datadir}/systemtap/tapset/libvirt_probes.stp \
    %{buildroot}/%{_datadir}/systemtap/tapset/libvirt_probes-64.stp
@@ -1414,6 +1427,9 @@ fi
 %dir /usr/lib/supportconfig/plugins
 /usr/lib/supportconfig/plugins/libvirt
 
+%files daemon-hooks
+%{_sysconfdir}/libvirt/hooks/qemu
+
 %files daemon-config-network
 %dir %{_datadir}/libvirt/networks/
 %{_datadir}/libvirt/networks/default.xml

suse-qemu-domain-hook.py

@@ -0,0 +1,331 @@
+#!/usr/bin/env python
+# libvirt hook script for QEMU/KVM domains. See the libvirt hooks
+# documenation for more details
+#
+#  https://www.libvirt.org/hooks.html
+#
+# Currently this hook looks for domains with <metadata> containing
+# configuration for dmmd <disk> devices.  All <metadata> sub-elements
+# must have a matching <disk> under <devices>. Those without a matching
+# <disk> will be ignored.
+#
+# The dmmd device syntax is similar to Xen's block-dmmd. E.g.
+#   md;/dev/md0(/etc/mdadm/mdadm.conf);lvm;/dev/vg/lv
+#
+# Device pairs (type;dev) are processed in order. The last device
+# should match a <source dev=> attribute of a <disk>. The following
+# configuration illustrates a domain with two dmmd devices
+#
+# <domain>
+#   ...
+#   <metadata>
+#     <hook:dmmd xmlns:hook='https://libvirt.org/schemas/domain/hooks/1.0'>
+#       <disk>md;/dev/md0(/etc/mdadm.conf);lvm;/dev/vg1/lv1</disk>
+#       <disk>md;/dev/md1(/etc/mdadm.conf);lvm;/dev/vg1/lv2</disk>
+#     </hook:dmmd>
+#   </metadata>
+#   <devices>
+#     ...
+#     <disk type='block' device='disk'>
+#       <driver name='qemu' type='raw'/>
+#       <source dev='/dev/vg1/lv1'/>
+#       <target dev='vdb' bus='virtio'/>
+#     </disk>
+#     <disk type='block' device='disk'>
+#       <driver name='qemu' type='raw'/>
+#       <source dev='/dev/vg1/lv2'/>
+#       <target dev='vdc' bus='virtio'/>
+#     </disk>
+#   </devices>
+# </domain>
+#
+#
+#  md devices can optionally:
+#   specify a config file through:
+#      md;/dev/md100(/var/opt/config/mdadm.conf)
+#   use an array name (mdadm -N option):
+#      md;My-MD-name;lvm;/dev/vg1/lv1
+
+import os
+import sys
+import time
+import subprocess
+from lxml import etree
+from subprocess import check_output
+from subprocess import CalledProcessError
+
+COMMAND_TIMEOUT = 60
+MDADM_BIN = "/sbin/mdadm"
+PVSCAN_BIN = "/sbin/pvscan"
+LVCHANGE_BIN = "/sbin/lvchange"
+HOOK_NAMESPACE = "https://libvirt.org/schemas/domain/hooks/1.0"
+HOOK_NS_TAG = "{%s}" % HOOK_NAMESPACE
+
+DEBUG = False
+
+def write_debug(msg):
+    if DEBUG:
+        with open("/var/log/libvirt/qemu/suse-qemu-hook-output.log", "a") as f:
+            f.write(msg + "\n")
+
+
+def run_cmd(cmd):
+    cmd_output = ""
+    rc = 0
+
+    msg = ""
+    for m in cmd:
+        msg += m + " "
+    write_debug("run_cmd executing: " + msg)
+        
+    try:
+        cmd_output = check_output(cmd, stderr=subprocess.STDOUT)
+    except CalledProcessError as err:
+        write_debug("run_cmd: caught CalledProcessError with output: " + err.output)
+        rc = err.returncode
+
+    if rc != 0:
+       write_debug("run_cmd failed: " + msg)
+
+    return [rc, cmd_output]
+
+
+def prepare_md(dev):
+    conf = []
+    mdadmopts = []
+    devpath = ""
+    startcfg = dev.find("(")
+
+    # check if MD config specifies a conf file for mdadm
+    if startcfg != -1:
+        endcfg = dev.find(")")
+        conf = ["-c"]
+        conf.append(dev[startcfg + 1:endcfg])
+        dev = dev[:startcfg]
+
+    # check if MD config contains a device or array name
+    if not dev.startswith("/"):
+        mdadmopts = ["-s"]
+        mdadmopts.append("-N")
+        devpath = "/dev/md/" + dev
+    else:
+        devpath = dev
+
+    # check if MD device is already active
+    cmd = [MDADM_BIN, "-Q"]
+    cmd.append(devpath)
+    write_debug("prepare_md: calling mdadm -Q for device " + devpath)
+    ret, cmd_output = run_cmd(cmd)
+    if ret == 0:
+        write_debug("prepare_md: mdadm -Q succeeded for device " + devpath + ". Already activated")
+        return 0
+
+    cmd = [MDADM_BIN, "-A"]
+    cmd.extend(mdadmopts)
+    cmd.extend(conf)
+    cmd.append(devpath)
+
+    write_debug("prepare_md: calling mdadm -A for device " + devpath)
+    ret, cmd_output = run_cmd(cmd)
+
+    if ret != 0:
+        write_debug("prepare_md: mdadm -A failed for device " + devpath)
+    else:
+        write_debug("prepare_md: mdadm -A succeeded for device " + devpath)
+    return ret
+
+
+def release_md(dev):
+    conf = []
+    devpath = ""
+    startcfg = dev.find("(")
+
+    if startcfg != -1:
+        endcfg = dev.find(")")
+        conf = ["-c"]
+        conf.append(dev[startcfg + 1:endcfg])
+        dev = dev[:startcfg]
+
+    # check if MD config contains a device or array name. For
+    # querying and deactivating a device name is required
+    if not dev.startswith("/"):
+        devpath = "/dev/md/" + dev
+    else:
+        devpath = dev
+
+    # check if device exists
+    cmd = [MDADM_BIN, "-Q"]
+    cmd.extend(conf)
+    cmd.append(devpath)
+
+    write_debug("release_md: calling mdadm -Q for device " + devpath)
+    ret, cmd_output = run_cmd(cmd)
+    if ret != 0:
+        write_debug("release_md: mdadm -Q failed for device " + devpath + ". Already deactivated")
+        return 0
+
+    cmd = [MDADM_BIN, "-S"]
+    cmd.extend(conf)
+    cmd.append(devpath)
+    write_debug("release_md: calling mdadm -S for device " + devpath)
+    ret, cmd_output = run_cmd(cmd)
+    if ret == 0:
+        write_debug("release_md: mdadm -S succeeded for device " + devpath)
+    else:
+        write_debug("release_md: mdadm -S failed for device " + devpath)
+
+    return ret
+
+
+def prepare_lvm(dev):
+    cmd = [LVCHANGE_BIN]
+    cmd.append("-aey")
+    cmd.append(dev)
+
+    endtime = time.time() + COMMAND_TIMEOUT;
+    while time.time() < endtime:
+        # When using MD devices for LVM PV, it is best to rescan for PV and VG
+        run_cmd([PVSCAN_BIN])
+        ret, cmd_output = run_cmd(cmd)
+        if ret == 0 and os.path.exists(dev):
+            write_debug("prepare_lvm: lvchange -aey succeeded on device " + dev)
+            return 0
+        else:
+            write_debug("prepare_lvm: lvchange -aey failed on device " + dev)
+        time.sleep(0.1)
+
+    write_debug("prepare_lvm: lvchange -aey never succeeded for device " + dev)
+    return 1
+
+
+def release_lvm(dev):
+    # Nothing to do if the device doesn't exist or is already deactivated
+    if not os.path.exists(dev):
+        write_debug("release_lvm: dev " + dev + " does not exist. Nothing to do!")
+        return 0
+
+    cmd = [LVCHANGE_BIN]
+    cmd.append("-aen")
+    cmd.append(dev)
+
+    endtime = time.time() + COMMAND_TIMEOUT;
+    while time.time() < endtime:
+        ret, cmd_output = run_cmd(cmd)
+        if ret == 0:
+            write_debug("release_lvm: lvchange -aen succeeded for device " + dev)
+            return 0
+        else:
+            write_debug("release_lvm: lvchange -aen failed for device " + dev + ". Trying again...")
+            
+        time.sleep(0.1)
+
+    write_debug("release_lvm: lvchange -aen never succeeded for device " + dev)
+    return 1
+
+
+def prepare_config(params):
+    write_debug("prepare_config: called with params " + params)
+    conf = params.split(";")
+    i = 0
+
+    while i < len(conf):
+        t = conf[i]
+        d = conf[i+1]
+        write_debug("prepare_config: got t = " + t + " and d = " + d)
+        if t == "md":
+            if prepare_md(d):
+                write_debug("prepare_config: failed to prepare MD device " + d)
+                return 1
+        if t == "lvm":
+            if prepare_lvm(d):
+                write_debug("prepare_config: failed to prepare LVM device " + d)
+                return 1
+        i += 2
+
+    return 0
+
+
+def release_config(params):
+    write_debug("release_config: called with params " + params)
+    conf = params.split(";")
+    i = len(conf) - 1
+    ret = 0
+
+    # work backwards through the list when releasing, cleaning
+    # up LVM first, then MD
+    while i >= 0:
+        t = conf[i-1]
+        d = conf[i]
+        write_debug("release_config: got t = " + t + " and d = " + d)
+        if t == "md":
+            if release_md(d):
+                write_debug("release_config: failed to release MD device " + d)
+                ret = 1
+        if t == "lvm":
+            if release_lvm(d):
+                write_debug("release_config: failed to release LVM device " + d)
+                ret = 1
+        i -= 2
+
+    return ret
+
+
+if len(sys.argv) < 3:
+    sys.exit(1)
+
+exit_code = 0
+disk_devs = []
+phase = sys.argv[2]
+vmxml = sys.stdin.read()
+
+tree = etree.fromstring(vmxml)
+devs = tree.xpath("/domain/devices/disk")
+dmmd_configs = tree.xpath("/domain/metadata/hook:dmmd/disk", namespaces={'hook': HOOK_NAMESPACE})
+
+if len(dmmd_configs) == 0:
+    write_debug("No dmmd configurations found in <metadata>")
+    sys.exit(0)
+
+write_debug("got phase: " + phase)
+
+# build a list of <disk type='block'> source device names to check against
+# dmmd configurations
+for d in devs:
+    val = d.get("type")
+    if val is None or val != "block":
+        continue
+
+    for child in d:
+        if child.tag == "source":
+            disk_devs.append(child.get("dev"))
+
+# For each dmmd configuration in <metadata>, check there is a corresponding
+# disk
+for config in dmmd_configs:
+    # check that a disk exists for this config. <disk> devices may have
+    # been added or removed without a corresponding update to <metadata>
+    index = config.text.rfind(";")
+    if index == -1:
+        continue
+
+    disk = config.text[index + 1:]
+    # remove config file specfied with '(/path/to/conf)'
+    if disk.endswith(")"):
+        index = disk.rfind("(")
+        if index == -1:
+            continue
+        disk = disk[:index]
+
+    if disk not in disk_devs:
+        write_debug("Ignoring config '" + config.text + "' with no matching <disk> device")
+        continue
+
+    # TODO: check that migration can be handled by the 'prepare' phase on
+    # destination and 'release' phase on source
+    if phase == "prepare":
+        exit_code = prepare_config(config.text)
+
+    if phase == "release":
+        exit_code = release_config(config.text)
+
+sys.exit(exit_code)