On Thu, Apr 14, 2016 at 11:27 AM, Gianluca Cecchi <[email protected]> wrote: > On Thu, Apr 14, 2016 at 8:15 AM, Yedidyah Bar David <[email protected]> wrote: >> >> On Thu, Apr 14, 2016 at 5:18 AM, Michael Hall <[email protected]> wrote: >> >> >> 3. NFS >> loop-back mounting nfs is considered risky, due to potential locking >> issues. Therefore, if you want to use NFS, you are better off doing >> something like this: >> > > Hello, > can you give more details about these potential locking issues? So that I > can reproduce
Most of what I know about this is: https://lwn.net/Articles/595652/ > I have 2 little environments where I'm using this kind of setup. In one of > them the hypervisor is a physical server, in the other one the hypervisor is > itself a libvirt VM inside a Fedora 23 based laptop. oVirt version is 3.6.4 > on both. > > The test VM has 2 disks sda and sdb; all ovirt related stuff on sdb > > My raw steps for the lab have been, after setting up CentOS 7.2 OS, > disabling ipv6 and NetworkManager, putting SELinux to permissive and > enabling ovirt repo: selinux enforcing should work too, if it fails please open a bug. Thanks. You might have to set the right contexts for your local disks. > > NOTE: I also stop and disable firewalld > > My host is ovc72.localdomain.local and name of my future engine > shengine.localdomain.local > > yum -y update > > yum install ovirt-hosted-engine-setup ovirt-engine-appliance > > yum install rpcbind nfs-utils nfs-server > (some of them probably already pulled in as dependencies from previous > command) > > When I start from scratch the system > > pvcreate /dev/sdb > vgcreate OVIRT_DOMAIN /dev/sdb > lvcreate -n ISO_DOMAIN -L 5G OVIRT_DOMAIN > lvcreate -n SHE_DOMAIN -L 25G OVIRT_DOMAIN > lvcreate -n NFS_DOMAIN -l +100%FREE OVIRT_DOMAIN > > if I only have to reinitialize I start from here > mkfs -t xfs -f /dev/mapper/OVIRT_DOMAIN-ISO_DOMAIN > mkfs -t xfs -f /dev/mapper/OVIRT_DOMAIN-NFS_DOMAIN > mkfs -t xfs -f /dev/mapper/OVIRT_DOMAIN-SHE_DOMAIN > > mkdir /ISO_DOMAIN /NFS_DOMAIN /SHE_DOMAIN > > /etc/fstab > /dev/mapper/OVIRT_DOMAIN-ISO_DOMAIN /ISO_DOMAIN xfs defaults 0 0 > /dev/mapper/OVIRT_DOMAIN-NFS_DOMAIN /NFS_DOMAIN xfs defaults 0 0 > /dev/mapper/OVIRT_DOMAIN-SHE_DOMAIN /SHE_DOMAIN xfs defaults 0 0 > > mount /ISO_DOMAIN/ --> this for ISO images > mount /NFS_DOMAIN/ ---> this for data storage domain where your VMs will > live (NFS based) > mount /SHE_DOMAIN/ --> this is for the HE VM > > chown 36:36 /ISO_DOMAIN > chown 36:36 /NFS_DOMAIN > chown 36:36 /SHE_DOMAIN > > chmod 0755 /ISO_DOMAIN > chmod 0755 /NFS_DOMAIN > chmod 0755 /SHE_DOMAIN > > /etc/exports > /ISO_DOMAIN *(rw,anonuid=36,anongid=36,all_squash) > /NFS_DOMAIN *(rw,anonuid=36,anongid=36,all_squash) > /SHE_DOMAIN *(rw,anonuid=36,anongid=36,all_squash) > > systemctl enable rpcbind > systemctl start rpcbind > > systemctl enable nfs-server > systemctl start nfs-server > > hosted-engine --deploy > > During setup I choose: > > Engine FQDN : shengine.localdomain.local > > Firewall manager : iptables > > Storage connection : > ovc71.localdomain.local:/SHE_DOMAIN > > OVF archive (for disk boot) : > /usr/share/ovirt-engine-appliance/ovirt-engine-appliance-20151015.0-1.el7.centos.ova > > Also, I used the appliance provided by ovirt-engine-appliance package > > After install you have to make a dependency so that VDSM Broker starts after > NFS Server > > In /usr/lib/systemd/system/ovirt-ha-broker.service > > Added in section [Unit] the line: > > After=nfs-server.service > > Also in file vdsmd.service changed from: > After=multipathd.service libvirtd.service iscsid.service rpcbind.service \ > supervdsmd.service sanlock.service vdsm-network.service > > to: > After=multipathd.service libvirtd.service iscsid.service rpcbind.service \ > supervdsmd.service sanlock.service vdsm-network.service \ > nfs-server.service > > NOTE: the files will be overwritten by future updates, so you have to keep > in mind... > > On ovc72 in /etc/multipath.conf aright after line > # VDSM REVISION 1.3 > > added > # RHEV PRIVATE > > blacklist { > wwid 0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-1 > wwid 0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0 > } > > To exclude both 2 internal drives... probably oVirt keeps in mind only the > first one? No idea > Otherwise many messages like: > Jan 25 11:02:00 ovc72 kernel: device-mapper: table: 253:6: multipath: error > getting device > Jan 25 11:02:00 ovc72 kernel: device-mapper: ioctl: error adding target to > table > > So far I didn't find any problems. Only a little trick when you have to make > ful lmaintenance where you have to power off the (only) hypervisor, where > you have to make the right order steps. I guess you can probably script that too... Thanks for sharing. As wrote above, no personal experience with loopback nfs. For the multipath question, if interested, perhaps ask again with a different subject. thanks for sharing! -- Didi _______________________________________________ Users mailing list [email protected] http://lists.ovirt.org/mailman/listinfo/users
