Uly.me – Page 4 – cloud engineer

Git Reset Hard

February 12, 2022 by Ulysses

Reset uncommitted changes to both files and directories.

git reset --hard

Remove untracked files and directories.

git clean -fd

GCP Compute Startup Script

February 12, 2022 by Ulysses

How to add startup and shutdown scripts on GCP Compute Engine.

Startup Script

gcloud compute instances add-metadata servername \
--project project-id \
--zone us-central1-c \
--metadata=startup-script='#! /bin/bash
sudo -i
echo "Time: $(date)" >> /tmp/date.txt'

Shutdown Script

gcloud compute instances add-metadata servername \
--project project-id \
--zone us-central1-c \
--metadata=shutdown-script='#! /bin/bash
# Shuts down Apache server
/etc/init.d/apache2 stop'

Linux prompt display current directory only

February 11, 2022 by Ulysses

Here’s the command to display only the current directory.

export PROMPT_DIRTRIM=1

Place the command in your ~/.bashrc to make it permanent.

Set Terminal Browser to Firefox

February 7, 2022 by Ulysses

Every time I log in to Google Cloud, it’s using the Chromium.

Set BROWSER env to Firefox instead.

export BROWSER=/usr/bin/firefox

gcloud auth login

Add it your .bashrc or .bashprofile if you want it to be permanent.

SFTP Command Line

February 6, 2022 by Ulysses

Here are command lines you can within SFTP.

sftp username@servername

Commands available from the local client.

lls
lcd
lmkdir
lpwd
lumask

Commands available on remote server.

cd
chmod
chown
exit
get
help
ln
ls
mkdir
put
pwd
rename
rm
rmdir
version
!

Extend LVM Logical Volume

February 5, 2022 by Ulysses

How to extend a LVM logical volume.

Extend the physical drive.

gcloud compute disks resize data-drive --size=40GB

SSH to a server and extend the physical volume.

$ pvresize /dev/sdb
  Physical volume "/dev/sdb" changed
  1 physical volume(s) resized or updated / 0 physical volume(s) not resized

$ pvs
  PV         VG Fmt  Attr PSize   PFree 
  /dev/sdb   vg lvm2 a--  <40.00g 10.00g

$ vgs
  VG #PV #LV #SN Attr   VSize   VFree 
  vg   1   1   0 wz--n- <40.00g 10.00g

$ lvs
  LV   VG Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  data vg -wi-ao---- <30.00g

Extend the logical volume.

$ lvresize -l +100%FREE /dev/vg/data
  Size of logical volume vg/data changed from <30.00 GiB (7679 extents) to <40.00 GiB (10239 extents).
  Logical volume vg/data successfully resized.

Check the volume size.

$ lsblk
NAME      MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda         8:0    0   20G  0 disk 
├─sda1      8:1    0  200M  0 part /boot/efi
└─sda2      8:2    0 19.8G  0 part /
sdb         8:16   0   40G  0 disk 
└─vg-data 253:0    0   40G  0 lvm  /mnt

Still at 30GB.

$ df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  385M     0  385M   0% /dev
tmpfs               tmpfs     403M     0  403M   0% /dev/shm
tmpfs               tmpfs     403M  5.5M  398M   2% /run
tmpfs               tmpfs     403M     0  403M   0% /sys/fs/cgroup
/dev/sda2           xfs        20G  2.9G   17G  15% /
/dev/sda1           vfat      200M  5.8M  195M   3% /boot/efi
/dev/mapper/vg-data xfs        30G  247M   30G   1% /mnt
tmpfs               tmpfs      81M     0   81M   0% /run/user/1001

Extend the file system.

$ xfs_growfs /dev/vg/data
meta-data=/dev/mapper/vg-data    isize=512    agcount=12, agsize=655360 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=7863296, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 7863296 to 10484736

Let’s check again.

$ df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  385M     0  385M   0% /dev
tmpfs               tmpfs     403M     0  403M   0% /dev/shm
tmpfs               tmpfs     403M  5.5M  398M   2% /run
tmpfs               tmpfs     403M     0  403M   0% /sys/fs/cgroup
/dev/sda2           xfs        20G  2.9G   17G  15% /
/dev/sda1           vfat      200M  5.8M  195M   3% /boot/efi
/dev/mapper/vg-data xfs        40G  319M   40G   1% /mnt
tmpfs               tmpfs      81M     0   81M   0% /run/user/1001

The logical volume is now at 40GB.

Setup LVM on a VM

February 5, 2022 by Ulysses

How to setup Logical Volume Manager on a VM.

Install LVM.

yum install lvm2

Check the disks available. We are going to run LVM on /dev/sdb.

$ lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   20G  0 disk 
├─sda1   8:1    0  200M  0 part /boot/efi
└─sda2   8:2    0 19.8G  0 part /
sdb      8:16   0   20G  0 disk

Create a physical volume on /dev/sdb.

$ pvcreate /dev/sdb
  Physical volume "/dev/sdb" successfully created.
$ pvs
  PV         VG Fmt  Attr PSize   PFree
  /dev/sdb   vg lvm2 a--  <20.00g    0

Create a volume group called vg.

$ vgcreate vg /dev/sdb
  Volume group "vg" successfully created
$ vgs
  VG #PV #LV #SN Attr   VSize   VFree  
  vg   1   0   0 wz--n- <20.00g <20.00g

Create a 10GB logical volume group called data.

$ lvcreate -L 10G -n data vg
  Logical volume "data" created.
$ lvs
  LV   VG Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  data vg -wi-a----- 10.00g

Format the volume group and mount it.

$ mkfs.xfs /dev/vg/data
meta-data=/dev/vg/data           isize=512    agcount=4, agsize=655360 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=2621440, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
Discarding blocks...Done.
$ mount /dev/vg/data /mnt

Check your logical volume. It says 10GB.

$ df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  385M     0  385M   0% /dev
tmpfs               tmpfs     403M     0  403M   0% /dev/shm
tmpfs               tmpfs     403M  5.5M  398M   2% /run
tmpfs               tmpfs     403M     0  403M   0% /sys/fs/cgroup
/dev/sda2           xfs        20G  2.9G   17G  15% /
/dev/sda1           vfat      200M  5.8M  195M   3% /boot/efi
tmpfs               tmpfs      81M     0   81M   0% /run/user/1000
/dev/mapper/vg-data xfs        10G  104M  9.9G   2% /mnt

Let’s now extend the logical volume to 20GB.

$ lvextend -l +100%FREE /dev/vg/data
  Size of logical volume vg/data changed from 10.00 GiB (2560 extents) to <20.00 GiB (5119 extents).
  Logical volume vg/data successfully resized.

Although lsblk says 20GB, our logical volume still says 10GB.

$ lsblk
NAME      MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda         8:0    0   20G  0 disk 
├─sda1      8:1    0  200M  0 part /boot/efi
└─sda2      8:2    0 19.8G  0 part /
sdb         8:16   0   20G  0 disk 
└─vg-data 253:0    0   20G  0 lvm  /mnt
$ df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  385M     0  385M   0% /dev
tmpfs               tmpfs     403M     0  403M   0% /dev/shm
tmpfs               tmpfs     403M  5.5M  398M   2% /run
tmpfs               tmpfs     403M     0  403M   0% /sys/fs/cgroup
/dev/sda2           xfs        20G  2.9G   17G  15% /
/dev/sda1           vfat      200M  5.8M  195M   3% /boot/efi
tmpfs               tmpfs      81M     0   81M   0% /run/user/1000
/dev/mapper/vg-data xfs        10G  104M  9.9G   2% /mnt

We need to grow the file system.

$ xfs_growfs /dev/vg/data
meta-data=/dev/mapper/vg-data    isize=512    agcount=4, agsize=655360 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=2621440, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 2621440 to 5241856

Let’s check again.

$ df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  385M     0  385M   0% /dev
tmpfs               tmpfs     403M     0  403M   0% /dev/shm
tmpfs               tmpfs     403M  5.5M  398M   2% /run
tmpfs               tmpfs     403M     0  403M   0% /sys/fs/cgroup
/dev/sda2           xfs        20G  2.9G   17G  15% /
/dev/sda1           vfat      200M  5.8M  195M   3% /boot/efi
tmpfs               tmpfs      81M     0   81M   0% /run/user/1000
/dev/mapper/vg-data xfs        20G  176M   20G   1% /mnt

It now says 20GB.

GCP Reset Windows Password

February 4, 2022 by Ulysses

How to reset password of a GCP Compute Engine running on Windows OS.

gcloud compute reset-windows-password servername \
--zone us-central1-a \
--project your-project-id

Output

This command creates an account and sets an initial password for the
user [firstname_lastname] if the account does not already exist.
If the account already exists, resetting the password can cause the
LOSS OF ENCRYPTED DATA secured with the current password, including
files and stored passwords.
 
For more information, see:
https://cloud.google.com/compute/docs/operating-systems/windows#reset
 
Would you like to set or reset the password for [firstname_lastname]
(Y/n)?  y
 
Resetting and retrieving password for [firstname_lastname] on [servername]
Updated [https://www.googleapis.com/compute/v1/projects/your-project-id/zones/us-central1-a/instances/servername].
WARNING: Instance [servername] does not appear to have an external IP
address, so it will not be able to accept external connections.
To add an external IP address to the instance, use
gcloud compute instances add-access-config.
password: xxxxxxxxxxxxxxx
username: firstname_lastname