The Best Docker Tutorial for Beginners
We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........
1. Let's work from an environment where we can install Ansible on.
If you are using an older version of Linux based on Mint 18 or Ubuntu 16, you may want to get the PPA and get the latest version of Ansible that way:
sudo add-apt-repository ppa:ansible/ansible
sudo apt update
Some bugs in older Ansible versions are where unarchive will retriev........
How To Enable HA in Proxmox
Test Your HA
Shutdown the node that has the HA VM.
zip is useful to share files across multiple platforms.
A simple way if you want to zip all pdfs:
zip Labs.zip *.pdf
If you want to zip everything in the current directory and subdirectories do this:
zip -r stuff.zip *........
How Do You Apply Changes You've Made?
You can make all kinds of changes to the switch, but remember they are not actually active until you run the "commit" command. This means adding or deleting config options will not have any effect until you run "commit".
Under configure mode:
This assumes your system is a fresh and normally working install.
What often happens is that many new devices have multiple audio outputs which are generally analog and HDMI/Digital out. Sometimes the OS defaults to the wrong one that you didn't want.
For example if your sound is supposed to play over the HDMI, perhaps the output is set to analog or vice versa.........
base64 has legitimate uses too and can be an easy way to store a file or data within actual code for developers to keep things in a single file.
For example let's take an image we'll see for an application's background:
base64 -w 0 some.jpg >some.jpg-base64
-w 0 makes it output to a single line which makes it easy to store in a variable. Without the -w 0 it will wrap over multiple lines.........
It is fairly simple to use once you know how to use it. However, the tricky thing is that by default it doesn't seem to be active or listen on any interface on manually specified.
How To Install ifplugd
First we install ifplugd
sudo apt install ifplugd
Let's enable it on our desired device(s)
set this line as so:........
Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery.
To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl".
1.) Install the utilities to make our bridge
sudo apt-get i........
There are multiple layers but most are enabled by default such as the setting in the Phone Device Settings.
However the one not enabled by default is the one in "Enterprise Phone Configuration".
Enable "Cisco Camera" and then reboot your phones to enable it.........
This may sound silly but often on the same machine multiple versions of SQL may be installed due to other applications.
How do we know which one we are running and connected to?
Use the query:
Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments.
Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
zenity is a nice utility as part of the gnome window manager that allows you to script from bash and retrieve the input from the user. It could also be helpful in just notifying a user when they login with a popup window.
I'll give an overview of what's available with zenity:
--calendar Display calendar dialog
--entry Display tex........
sudo apt-get install libcurl4-openssl-dev git build-essential autotools-dev autoconf libcurl3
sudo apt-get install libcurl4-gnutls-dev
git clone https://github.com/wolf9466/cpuminer-multi
sudo apt-get install cmake libpthread-* libmicrohttpd-dev libssl-dev libhwloc-dev
git clone https://github.com/fireice-uk/xmr-stak-cpu.git
chmod +x xmr-stak-cpu
./xmr-stak -O xmr........
This happens because Dovecot limits the maximum IMAPconnections per IPto just 10. This may be fine for a single client side IPbut if an entire office or multiple users are behind one IPor a single heavy user is active then you will get bizarre errors in your e-mail clients such as "Password Incorrect" or similar in Thunderbird. It won't be obvious on the client side as to what the problem is and they will probably just think the server is misconfi........
I am using a GTX 1060 but replace the download for the driver with the correct/current version for your particular card by visiting: http://www.nvidia.com/Download/index.aspx?lang=en-us
yum install automake curl openssl-devel libcurl-devel gcc gcc-c++
yum -y install kernel-devel-`uname -r`
yum -y install unzip
I was sure this was a Centos bug with OpenSSL, Apache, MySQL or even PHP. I tried everything but nothing helped. One clue is that if you check the Apache logs you will see nothing in the access logs until minutes later (this means Firefox has not even passed your request to the remote Apache/htttpd server).
When even accepting the invalid certificate message that would show up minutes later when trying to "View the Certificate" Firefox would freeze. This bu........
To grant the IP 192.168.2.4 to user mysqlguy
GRANT ALL ON *.* TO 'mysqlguy'@'192.168.2.4';
To allow any IPfor mysqlguy just use the wildcard % character
GRANT ALL ON *.* TO 'mysqlguy'@'%';
Also note it is normal and fine to have multiple entries in the mysql table.........
You can actually just pass multiple "-L" statements to achieve this.
An example is as below:
ssl -L 80:192.168.10.5:80 -L443:192.168.10.5:443 -L2068:192.168.10.5:2068 -L 8192:192.168.10.5:8192 email@example.com
The above essentially is saying forward ports 80,443,2068,8192 to the remote IPof 192.168.10.5 (even though it is behind NAT). Essentially SSH will do the NAT part even if the........
yum -y install --skip-broken package-you-want-to-install
Packages skipped because of dependency problems:
php56w-mysql-5.6.30-1.w6.x86_64 from webtatic
Error: Multilib version problems found. This often means that the root
cause is something else and multilib version checking is just
pointing out that there is........
This is actually very simple and this example assumes your network device is "eth0"
In Centos your network config would be the following: /etc/sysconfig/network-scripts/ifcfg-eth0
Take the same path and just add a "-range0"
So to add a range create the following file: /etc/sysconfig/network-scripts/ifcfg-eth0-range0
Say you have a path like this "/some/path/here with spaces/". If you try to transfer it you will get a message along the lines of:
scp -rp 192.168.0.12:"/some/path/here space/" .
scp: /some/path/here: No such file or directory
scp: space: No such file or directory
You can escape each space but what a pain that is especially if you have multiple spaces in the path.
The simplest way is to use the follow........
iptables -t nat -A PREROUTING -p tcp -m multiport --dports 80,443,2068,8192 -j DNAT --to-destination 192.168.1.175
Just adjust the "--dports" to the ports you need and the --to-destination to the destination IP (note it must be on the same network as the server running iptables........
The above site has the patch that does this essentialy turning a Desktop Windows into a full fledged RDP server.........
On some CPanel installs we see complaints of "/usr/local/cpanel/bin/apache_conf_distiller" causing 100% cpu usage without any solution.
Killing the process causes it to spawn again, actually it seems it tends to spawn multiple processes itself.
Restarting CPanel itself is a temporary but not permanent solution.........
VBox/Virtualbox solution to NS_ERROR_CALL_FAILED error
This is likely because you have 2D/3D acceleration enabled and your card doesn't support it.
Eg. you switched video card drivers or video cards that did support it.
The funny thing is that you CANNOT disable those options as they are "greyed" out in the VBox client GUI.
The config file has to be manually changed and fixed with these options "accelerate3D="false" accelera........
Iread this article and still don't understand the issue.
If I understand correctly the client negotiates after the first SSLconnection and then gets the correct hostname and thus correct certificate.
To their credit I know I'm not using SNIbecuase Iget this message in the Apache log :)
[warn] Init: You should not use name-based virtual hosts in conjunction with SSL!!
I've got one of these for testing projects from work at home and got more than I bargained for with the time I've spent on it due to the storage handing/Perc 6/i cards.
My particular model came with the following:
2U Rack Mount Server with Rails
2xOpteron 2373 EE (Quad Core, there is a 6-core version that can be found at times)
2 x 250GB Seagate SATA
2 x Dell Perc 6/i (horrible and a nightmare to work........
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to 192.168.1.253 [192.168.1.253] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/id_rsa type 1
debug1: identity file /root/.ssh/id_d........
Here's what SMART tells me the serial number is:
=== START OF INFORMATION SECTION ===
Device Model: Hitachi HDS721010CLA332
Serial Number: JP2940HQ3ZY7KH
Firmware Version: JP4OA3EA
User Capacity: 1,000,204,886,016 bytes
Device is: Not in smartctl database [for details use: -P showall]
ATA Version is: 8
ATA Standard is:&nb........
The size of the message you are trying to send exceeds a temporary size limit of the server. The message was not sent; try to reduce the message size or wait some time and try again. The server responded: 4.5.3 Error: too many recipients.
We set this in main.cf:
We didn't specify it before and the default is said to be 0/unlimited and it still didn't change anything.........
ip_conntrack: table full, dropping packet.
A lot of clients I've seen have this issue, it really seems the default level is way too small. Once this connection tracking table becomes full then packets get dropped which is obviously a bad thing.
One thing to be mindful of though is that 350 bytes of memory are used per entry so there is some justification for not keeping it too high. However, if you have multiple servers running or high traffic daemons........
For years I've always built cheap systems believing that there is little difference in more expensive components when it comes to reliability and quality, I generally believe this still except for Power Supplies.
I've always bought cheap cases with nice sounding 350-550W stock/cheap/crap power supplies and haven't had any issues for the most part until recently.
One such case is an NGEAR case with a 550W Optimax power supply, I always read that these supplies don't produce the........
Have you ever found a website/page that has several or perhaps dozens, hundreds or thousands of files that you need downloaded but don't have the time to manually do it?
wget's recursive function called with -r does that, but also with some quirks to be warned about.
If you're doing it from a standard web based directory structure, you will notice there is still a link to .. and wget will follow that.
Eg. let's say you have files in http://serverip/documen........
A few days ago this happened on multiple Centos 5 servers and apparently anyone using rpmforge was affected by this error and there was no solution other than disabling that repo to fix it.
To some this highlighted a few points, that there is a reason RHELexists with full paid support, and also that this could be a vulnerability and huge flaw with yum. A yum search or install should not segfault just because the rpmforge repo goes down.
Fortunately it came back up........
I thought only a faster CPUand SSDwould help but I already have a Quad-Core CPU and it wasn't being maxed out. The actual tests were performed on an AMD-V enabled 128MB dual core VMWare container though.
There is a flag that can be passed to make in order to start multiple threads, by specifying 4 threads I was able to reduce the whole kernel compilation time from scratch by about 50%! (65minutes vs 31minutes!). *Yes I did do a make clean before each co........
I'm posting this because it wasn't easy or obvious how this would be accomplished and the man page leaves it to guesswork.
Use "ImageMagick" which can be installed easily on most UNIX/Linux distros.
Remember that it will go with the standard file listing to determine the order but I believe you can manually specify multiple jpg's in the arguments.
Convert image/jpg to PDF
convert *.jpg yourpdf.pdf
This is a very handy and free tool.
Convert DOC/TXT documents to PDF
If you wanted to convert a .doc file or text........
I keep getting messages like this shortly after using the proxy (it works for a few seconds/page loads and then stops):
channel 12: open failed: administratively prohibited: open failed
I'm not sure what the issue is unless there's some kind of hardware firewall on the other end. I've used this exact configuration on multiple servers with no issue and even disabled iptables etc..........
Importing Plesk 8.6 Backup to Virtualmin:
Validating migration file ..
.. validation failed : XML::Simple Perl module is not installed
Solution is to install the correct module:
perl -MCPAN -e 'install XML::Simple'
Migrating a single domain works just fine, but it doesn't work with a full client backup containing multiple domains.........
crontab not working
It is running as user Apache
I've tried 0 0 * * * (which means midnight 00:00) and it does run at midnight but also 13:25 for some reason?
25 0 * * * with this it runs at 00:25 but again also at 13:25
Solution - Restart the Cron Service (especially if you changed your time/timezone)
*Update I had a suspicion that changing the timezone a few weeks ago caused this. I restarted lhe cron service and the problem h........
Remember to replace "eth0" with your NIC device although usually it will be eth0.
Replace 192.168.1.1 with your default gateway, remember you can also add multiple gateways by adding a second/different default gateway.
Kernel IP routing table
Destination Gateway Genmask&nb........
It simply doesn't work, the Apache VHOSTS remain 100% unchanged, why does this script exist? I'm sure it would work from the control panel but I am locked out because my IP was changed and it doesn't match the CPanel license. I wish CPanel would make it easier to update the license IP.
I even took it a step farther, I manually edited the vhosts and restarted Apache and it........
Mencoder is great, you can throw anything at it, including video files from your camera and have it encode into xvid or almost any other format.
In my case I took 640x480 video from my Canon and reduced the size by 1/3 with the options below (there are many other options that you can read about in the manual but I like to keep it simple).
mencoder -ovc xvid -oac mp3lame -xvidencopts fixed_quant=4 -o ........
This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc..
curlftpfs - mount a ftp host as a local directory
Basically the two main types of distros are Debian and RHEL/Centos based. I'm just going to give a quick overview of how the configuration of IP interfaces works in Debian/Centos based distros.
*Just one thing to remember, when setting IPs statically you have to manually specify a DNS server in /etc/resolv.conf (since DHCP is what normally does it automatically)
The IP (DHCP &........
It's very common to have multiple GCC versions for different reasons, as annoying as it is. Some newer/older programs only compile properly or at all on specific versions.
You can export the following variable CC:
Replace gcc-4.1 with the filename of the gcc you want eg. gcc-99........
MySQL SELECT with multiple where conditionsI can get a match on rows for now apparent reason
[quote:09cf04e097]SELECT * FROM TABLE WHERE field = 'value' & value = 'field'
To make it work as expected use 'AND' instead of '&' they seem to have a completely different and unexpected effect.
[quote:09cf04e097]SELECT * FROM TABLE WHERE field = 'value' AND value = 'field'
Use Mozilla Firefox, not Internet Explorer - You'll be glad!Hey guys,
I just thought I'd recommend that everyone switch to Mozilla Firefox as their web browser. You can find it at http://mozilla.org
It is free and it is much better than IE. It has a built-in popup blocker which works great and most importantly, it doesn't have a million critical security flaws which could compromise your security such as passwords for on-line banking etc..........
This really is a difficult and confusing process for non-Mandarin speakers, but here's what I've done and learned so far:
You can purchase an "M-Zone" China Mobile pre-paid SIMCard from almost anywhere but I tried to purchase mine from Suning (a large electronics dealer) hoping they would be able to help me or answer my questions but my plan didn't work out at all. At Suning once I found someone who spoke some English they gave me the 55 RMB M-Zone China Mobile P........
Ithink there has been a lot of negative press towards Rackable Systems. We will give their new solution credit that it is marketed very well, and comes prepackaged and ready to go.
But let's cut through the hype of both sides, the people who love this concept and the people who hate it.
What Rackable Systems have done is a first, to minimize space, power and costs into small servers. This is great, and many companies have already built their own servers based........