In Part I we'll go through the bare metal installation process, focusing on the post OS installation steps. The build used Ubuntu Server 18.04.1 as the base and we pick it up after the installer has worked its magic. Ensure you install on LVM2 which will let you snapshot your root volume and revert any unwanted changes, and to create consistent backups which you can store separately.
It's assumed that you can now remotely log in via ssh and elevate your privileges via sudo.
Let's first take a look at the storage configuration on the physical host:
It's assumed that you can now remotely log in via ssh and elevate your privileges via sudo.
Let's first take a look at the storage configuration on the physical host:
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| gsw@goat-lin:~$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda3 ubuntu-vg lvm2 a-- 110.79g 106.79ggsw@goat-lin:~$ sudo pvdisplay --- Physical volume --- PV Name /dev/sda3 VG Name ubuntu-vg PV Size 110.79 GiB / not usable 0 Allocatable yes PE Size 4.00 MiB Total PE 28363 Free PE 27339 Allocated PE 1024 PV UUID zA096A-SzzE-y732-54Pl-hYRu-TaDB-ANVGD2gsw@goat-lin:~$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert ubuntu-lv ubuntu-vg -wi-ao---- 4.00g |
gsw@goat-lin:~$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda3 ubuntu-vg lvm2 a-- 110.79g 106.79g gsw@goat-lin:~$ sudo pvdisplay --- Physical volume --- PV Name /dev/sda3 VG Name ubuntu-vg PV Size 110.79 GiB / not usable 0 Allocatable yes PE Size 4.00 MiB Total PE 28363 Free PE 27339 Allocated PE 1024 PV UUID zA096A-SzzE-y732-54Pl-hYRu-TaDB-ANVGD2 gsw@goat-lin:~$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert ubuntu-lv ubuntu-vg -wi-ao---- 4.00g
We can see that we have a 110GB physical disk and an initial volume of 4GB. Whilst this will be enough for the initial setup I'd recommend you use 10GB to avoid resizing later. The small size helped to speed up some of the backup process which is explored in a later post.
Now let's try out a simple volume snapshot. We can see the snapshot has been created and can mount it to inspect the filesystem contents.
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| gsw@goat-lin:~$ sudo lvcreate -s -L 4GB -n snap_test ubuntu-vg/ubuntu-lv Using default stripesize 64.00 KiB. Logical volume "snap_test" created.gsw@goat-lin:~$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert snap_test ubuntu-vg swi-a-s--- 4.00g ubuntu-lv 0.02 ubuntu-lv ubuntu-vg owi-aos--- 4.00gsudo mount /dev/mapper/ubuntu--vg-snap_test /mnt/test/gsw@goat-lin:~$ cd /mnt/test/gsw@goat-lin:/mnt/test$ lsbin dev home initrd.img.old lib64 media opt root sbin srv tmp var vmlinuz.oldboot etc initrd.img lib lost+found mnt proc run snap sys usr vmlinuz |
gsw@goat-lin:~$ sudo lvcreate -s -L 4GB -n snap_test ubuntu-vg/ubuntu-lv Using default stripesize 64.00 KiB. Logical volume "snap_test" created. gsw@goat-lin:~$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert snap_test ubuntu-vg swi-a-s--- 4.00g ubuntu-lv 0.02 ubuntu-lv ubuntu-vg owi-aos--- 4.00g sudo mount /dev/mapper/ubuntu--vg-snap_test /mnt/test/ gsw@goat-lin:~$ cd /mnt/test/ gsw@goat-lin:/mnt/test$ ls bin dev home initrd.img.old lib64 media opt root sbin srv tmp var vmlinuz.old boot etc initrd.img lib lost+found mnt proc run snap sys usr vmlinuzNow that we have a mechanism to roll back unwanted changes, we can forge ahead with adding some new packages. Don't forget that you can also revert your snapshots with lvconvert --merge ubuntu-vg/snap_test. However, you may find that keeping your snapshots on the server's local disk can consume space over time, or can be lost if there's a failure or rebuild so we look at an alternative approach next. I create an NFS export/share on my NAS and make it available to the server. I can use this to store disk images on more durable storage and can retrieve them whenever I need them down the track. Here we install the nfs client package and update /etc/fstab to mount the share on boot.
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| sudo apt-get install nfs-commongsw@goat-lin:/mnt$ cat /etc/fstabUUID=af8bea23-be3c-11e8-bc12-1c6f65319988 / ext4 defaults 0 0UUID=af8bea22-be3c-11e8-bc12-1c6f65319988 /boot ext4 defaults 0 0192.168.1.2:/volume2/Scratch /mnt/scratch nfs auto,noatime,nolock,bg,nfsvers=4,intr,tcp,actimeo=1800 0 0 |
sudo apt-get install nfs-common gsw@goat-lin:/mnt$ cat /etc/fstab UUID=af8bea23-be3c-11e8-bc12-1c6f65319988 / ext4 defaults 0 0 UUID=af8bea22-be3c-11e8-bc12-1c6f65319988 /boot ext4 defaults 0 0 192.168.1.2:/volume2/Scratch /mnt/scratch nfs auto,noatime,nolock,bg,nfsvers=4,intr,tcp,actimeo=1800 0 0Next, we identify the device containing our snapshot and back it up using dd to the NFS mount.
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| gsw@goat-lin:/mnt$ lsblkNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTloop0 7:0 0 87.9M 1 loop /snap/core/5328loop1 7:1 0 86.9M 1 loop /snap/core/4917sda 8:0 0 111.8G 0 disk├─sda1 8:1 0 1M 0 part├─sda2 8:2 0 1G 0 part /boot└─sda3 8:3 0 110.8G 0 part ├─ubuntu--vg-ubuntu--lv-real 253:0 0 4G 0 lvm │ ├─ubuntu--vg-ubuntu--lv 253:2 0 4G 0 lvm / │ └─ubuntu--vg-snap_test 253:3 0 4G 0 lvm └─ubuntu--vg-snap_test-cow 253:1 0 4G 0 lvm └─ubuntu--vg-snap_test 253:3 0 4G 0 lvmgsw@goat-lin:/mnt/scratch$ sudo dd if=/dev/mapper/ubuntu--vg-snap_test bs=64K conv=noerror,sync status=progress | gzip -c > /mnt/scratch/goat-lin/base_install.20180923.img.gz4250075136 bytes (4.3 GB, 4.0 GiB) copied, 95 s, 44.7 MB/s65536+0 records in65536+0 records out4294967296 bytes (4.3 GB, 4.0 GiB) copied, 95.6187 s, 44.9 MB/s |
gsw@goat-lin:/mnt$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 87.9M 1 loop /snap/core/5328
loop1 7:1 0 86.9M 1 loop /snap/core/4917
sda 8:0 0 111.8G 0 disk
├─sda1 8:1 0 1M 0 part
├─sda2 8:2 0 1G 0 part /boot
└─sda3 8:3 0 110.8G 0 part
├─ubuntu--vg-ubuntu--lv-real 253:0 0 4G 0 lvm
│ ├─ubuntu--vg-ubuntu--lv 253:2 0 4G 0 lvm /
│ └─ubuntu--vg-snap_test 253:3 0 4G 0 lvm
└─ubuntu--vg-snap_test-cow 253:1 0 4G 0 lvm
└─ubuntu--vg-snap_test 253:3 0 4G 0 lvm
gsw@goat-lin:/mnt/scratch$ sudo dd if=/dev/mapper/ubuntu--vg-snap_test bs=64K conv=noerror,sync status=progress | gzip -c > /mnt/scratch/goat-lin/base_install.20180923.img.gz
4250075136 bytes (4.3 GB, 4.0 GiB) copied, 95 s, 44.7 MB/s
65536+0 records in
65536+0 records out
4294967296 bytes (4.3 GB, 4.0 GiB) copied, 95.6187 s, 44.9 MB/s
With the backup created, we can now create a new volume to restore the data.
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| gsw@goat-lin:/mnt/scratch$ sudo lvcreate -L 4GB -n restore_test ubuntu-vg Logical volume "restore_test" created.gsw@goat-lin:/mnt/scratch$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert restore_test ubuntu-vg -wi-a----- 4.00g snap_test ubuntu-vg swi-a-s--- 4.00g ubuntu-lv 0.64 ubuntu-lv ubuntu-vg owi-aos--- 4.00g |
gsw@goat-lin:/mnt/scratch$ sudo lvcreate -L 4GB -n restore_test ubuntu-vg Logical volume "restore_test" created. gsw@goat-lin:/mnt/scratch$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert restore_test ubuntu-vg -wi-a----- 4.00g snap_test ubuntu-vg swi-a-s--- 4.00g ubuntu-lv 0.64 ubuntu-lv ubuntu-vg owi-aos--- 4.00gThe volume is created, so time to invoke the restore, again using dd.
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| gsw@goat-lin:/mnt/scratch$ sudo gunzip -c /mnt/scratch/goat-lin/base_install.20180923.img.gz | sudo dd of=/dev/mapper/ubuntu--vg-restore_test status=progress4289700352 bytes (4.3 GB, 4.0 GiB) copied, 199 s, 21.5 MB/s8388608+0 records in8388608+0 records out4294967296 bytes (4.3 GB, 4.0 GiB) copied, 200.069 s, 21.5 MB/sgsw@goat-lin:/mnt/scratch$ sudo mount /dev/mapper/ubuntu--vg-restore_test /mnt/test/gsw@goat-lin:/mnt/scratch$ ls /mnt/test/bin dev home initrd.img.old lib64 media opt root sbin srv tmp var vmlinuz.oldboot etc initrd.img lib lost+found mnt proc run snap sys usr vmlinuz |
gsw@goat-lin:/mnt/scratch$ sudo gunzip -c /mnt/scratch/goat-lin/base_install.20180923.img.gz | sudo dd of=/dev/mapper/ubuntu--vg-restore_test status=progress 4289700352 bytes (4.3 GB, 4.0 GiB) copied, 199 s, 21.5 MB/s 8388608+0 records in 8388608+0 records out 4294967296 bytes (4.3 GB, 4.0 GiB) copied, 200.069 s, 21.5 MB/s gsw@goat-lin:/mnt/scratch$ sudo mount /dev/mapper/ubuntu--vg-restore_test /mnt/test/ gsw@goat-lin:/mnt/scratch$ ls /mnt/test/ bin dev home initrd.img.old lib64 media opt root sbin srv tmp var vmlinuz.old boot etc initrd.img lib lost+found mnt proc run snap sys usr vmlinuz
The backup and restore process appears to work. It's worth noting sometimes you will need to update your package management config (main, universe, restricted, multiverse) in order to see some packages that may be required. Here's how you can accomplish this:
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| gsw@goat-lin:~$ sudo add-apt-repository main'main' distribution component is already enabled for all sources.gsw@goat-lin:~$ sudo add-apt-repository universe'universe' distribution component enabled for all sources. |
gsw@goat-lin:~$ sudo add-apt-repository main 'main' distribution component is already enabled for all sources. gsw@goat-lin:~$ sudo add-apt-repository universe 'universe' distribution component enabled for all sources.Finally, double check your installation is using the right timezone. There are a few ways of doing this via the installer, but if you skipped that step you can simply:
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| gsw@goat-lin:/etc/xen-tools$ sudo ln -sf /usr/share/zoneinfo/Australia/Melbourne /etc/localtime |
gsw@goat-lin:/etc/xen-tools$ sudo ln -sf /usr/share/zoneinfo/Australia/Melbourne /etc/localtime
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