How to Boot Single User Mode in RedHat/CentOS

Edit Grub Boot OptionsSingle User Mode (sometimes known as Maintenance Mode) is a mode in Unix-like operating systems such as Linux operate, where a handful of services are started at system boot for basic functionality to enable a single superuser perform certain critical tasks.

It is runlevel 1 under system SysV init, and runlevel1.target or rescue.target in systemd. Importantly, the services, if any, started at this runlevel/target varies by distribution. It’s generally useful for maintenance or emergency repairs (since it doesn’t offer any network services at all), when a computer is not capable of normal operations.

Once you have decided to enter single user mode for maintenance or recover from crash you will need to VNC to the server or in other words emulation of physical console.  Don’t worry about logging into the server at this point, since this process will need you to reboot the server.

The process is the same for both RedHat/CentOS 7 and 8

Once you issue the hard reboot, you may need to click Refresh in the top right of the VNC screen since the hard reboot will reset that connection. You need to click this refresh very quickly otherwise you will miss the boot screen where you can interrupt the boot process. Continue reading

How to Boot Single User Mode in Ubuntu

Ubuntu

Single User Mode (sometimes known as Maintenance Mode) is a mode in Unix-like operating systems such as Linux operate, where a handful of services are started at system boot for basic functionality to enable a single superuser perform certain critical tasks.

It is runlevel 1 under system SysV init, and runlevel1.target or rescue.target in systemd. Importantly, the services, if any, started at this runlevel/target varies by distribution. It’s generally useful for maintenance or emergency repairs (since it doesn’t offer any network services at all), when a computer is not capable of normal operations.

Once you have decided to enter single user mode for maintenance or recover from crash you will need to VNC to the server or in other words emulation of physical console.  Don’t worry about logging into the server at this point, since this process will need you to reboot the server.

Once you issue the hard reboot, you may need to click Refresh in the top right of the VNC screen since the hard reboot will reset that connection. You need to click this refresh very quickly otherwise you will miss the boot screen where you can interrupt the boot process. Continue reading

MSSQL SSISDBBackup.bak could not be accessed

If you get the error SSISDBBackup.bak could not be accessed while creating an Integration Services Catalog, it could be because you do not have Integration Services installed on your SQL Server instance. Below I am going to attempt and create an Integration Services Catalog, by right clicking the item within SSMS and choosing Create Catalog. If you are going to run/manage many SSIS packages, using a catalog makes life a lot easier. Continue reading

Fail2ban: Found no accessible config files for ‘filter.d/sshd-ddos’

Fail2banUpon enabling ssh-ddos jail in Fail2ban jail.local you may have the following errors:

Jail ‘sshd-ddos’ skipped, because of wrong configuration: Unable to read the filter ‘sshd-ddos’

and

Found no accessible config files for ‘filter.d/sshd-ddos’

The reason is that Continue reading

GitHub Desktop Commit failed – exit code 1 received

GitHub-Desktop-commit-failed-exitcode-1-received
The error in GitHub Desktop “Commit failed – exit code 1 received” can occur due to a few reasons.
Check first if you have added files to your index.
Open the command line and check your git status.

Second, check if you have nested .git directories.
Try searching your repository to see if you have multiple .git directories Continue reading

How To Restore AWS EC2 instance from a snapshot

Amazon-Web-Services-logoI have been working with Hyper-V checkpoints for a while and have been really impressed with the speed at which I can revert my instances when something goes wrong with an update or install.

So I expected similar approach in AWS EC2 and found  that restoring from a snapshot AWS EC2 is definitely not as easy as just right-clicking in Hyper-V.

From the documentation provided by AWS the following restoring from a snapshot AWS EC2 manual were loomed

Continue reading

Cannot impersonate user for data source ‘CDRDB’. (rsErrorImpersonatingUser)

skype-for-businessWhen deploying the Skype for Business Archiving and Monitoring role, it asks for a user account and password. Many clients don’t have a service account for this (or simply don;t understand they need a service account for this) and just put in the username and password of the Administrator or the person doing the install. Then, months later, they change the password on that account and can’t figure out why the Monitoring Server reports throws the error: Continue reading

How to save username and password in Git

In this article I’ll show how you can avoid entering your Git username and password for every push.

I’ll show three methods: Git SSH authorization, Git credentials caching, and Git credentials saving using credential.helper. Continue reading

How to remove ads from Xiaomi phones with MIUI

Xiaomi-MIUI-AdsMuch like Google and Amazon, Xiaomi doesn’t consider itself a hardware manufacturer, but an internet company which happens to make hardware. The company has promised to forever cap hardware profit margins at 5%. All this means is (similar to the other tech giants) Xiaomi needs to make money in other ways. One of them is by offering add-ons, extra services, and gaining revenue through ads.
Of course ads can be really annoying and that’s how to disable ads in Xiaomi MIUI: Continue reading

How to store /var on a separate partition

UbuntuWhat is the correct way to store /var on a separate partition?

First prepare a new partition (e.g. with parted or fdisk and mkfs).

For example, let’s create a new partition in fdisk:

then choose n for the new partition and go through configuration steps.
choose w at the end to write changes to a disk. Continue reading

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