tor browser

Tor Hidden Service in Ubuntu/Debian

tor browser

To install tor on Ubuntu/Debian, run

Default configuration file for tor is /etc/tor/torrc

To enable hidden service, edit /etc/tor/torrc

uncomment lines

Create folder for your hidden service

You need to install Apache/Nginx etc.. to serve your web application. Make sure to configure web application listen on 127.0.0.0:80

Now restart tor with command

Ubuntu/Debian support multiple instances of tor. You can use command “/usr/sbin/tor-instance-create” to create new tor instance. Configuration for instanced tor available at /etc/tor/instances/INSTANCE_NAME/torrc

To see URL for your Hidden service, run

Example

You should be able to visit the application using .onion link in Tor Browser.

You need to take backup of tor folder (/var/lib/tor/hidden_service) as it contains your secret keys, this is needed to use the .onion domain name. If you lose this, you will lose the .onion url.

To start the service on boot, run

See Tor

proxmox-6

Proxmox 6 disable No valid subscription notice

To disable No valid subscription notice from proxmox, edit file

Find

This is on line 380. inside function checked_command

Replace with

Resart pveproxy

Zimbra webmail not working on port 80/443

On Zimbra mail server, webmail stopped working on Port 80/443. Admin interface worked properly on url https://hostname:7071/. There is no errors displayed under monitor tab of Zimbra Admin.

To fix, run

After running this, netstat -lntp start showing nginx running on port 80 and 443

virt-manager kvm

virt-manager

virt-manager is a GUI tool to manage virtual machines.

On CentOS desktop, install it with

For installing on Ubuntu, see Install virt-manager on Ubuntu

Connect to remote KVM server

To connect to remote KVM server from virt-manager, Go to File > Add Connection

virt-manager kvm

If SSH port is not 22, use IP:PORT format to connect to KVM installation.

Once connected, you will see all VMs. Here we have 1 VM with name “foo”

You can double click on a VM to access its console/desktop.

virt-manager console

See kvm

VMWare ESXi

Clone VM on VMware ESXi using vmkfstools

Free version of VMware ESXi don’t provide option to clone virtual machine. If you want to clone a VM, you need to purchase expensive vSphere license.

There is a work around for this, you need to clone disk of an existing Virtual machine using vmkfstools.

To make clone of a VM disk, SSH into your VMWare ESXi server as user root. Then create clone of disk with

For new VM, i created a directory. Path to datastore directory may be differnt on your server, you can find it using “df -h” command and checking the file system.

Shutdown the Virtual Machine you want to clone the disk from. Run

In screenshot below, i first tried to clone with out creating destination folder. That resulted in error. After creating destination folder, vmkfstools command worked.

vmkfstools

Creating VM using cloned disk

Login to VMware ESXi web interface. Create a new VM. On the step where you select hardware, delete existing Disk. Add a new disk, browse and select the newly created clone disk. In this case – “/vmfs/volumes/disk2/ubuntu-clone/ubuntu-clone.vmdk”

VMWare ESXi

Once the VM creation is finished, you will be able to start the new VM. You can create a VM, then use it as template for creating new virtual machines.

See VMWare

vmstat

vmstat 1

* High values in “wa” column mean: IO problem
* High values in “si”, “so” mean: excessive swapping

Sustained high swap rates (si and so) are usually bad. The system will start spending all of its time swapping, and make no progress on any actual work. You will also see the number of runnable (r and b) processes increase. If the situation gets bad enough and free memory gets too low, the Out-of-memory (oom) logic will start killing random processes. At this point, either reducing the number of processes that normally run or adding additional RAM are about the only options.

vmstat – Report virtual memory statistics

vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.

The first report produced gives averages since the last reboot. Additional reports give information on a sampling period of length delay. The process and memory reports are instantaneous in either case.

FIELD DESCRIPTION FOR VM MODE

FIELD DESCRIPTION FOR DISK MODE

FIELD DESCRIPTION FOR DISK PARTITION MODE

FIELD DESCRIPTION FOR SLAB MODE

Related commands

* iostat
* sar
* mpstat
* ps
* top
* free

See Linux Commands

vgcreate

To Create a volumegroup.

See lvm