I am currently using ipxe to support system installation for virtual machines. Some scripts from github do helped me a lot. But I still don't know the meaning of some code, suck like:
set 210:string ${boot-url}sysrcd-${sysrcd-version}-x86/isolinux/
set 209:string isolinux.cfg
set filename ${210:string}pxelinux.0
what do 209 and 210 mean? The official manual does not provide enough information.
http://ipxe.org/cmd/set
This is how iPXE works.
Client (with iPXE firmware) requests a dynamic IP from the DHCP server.
DHCP server offers an IP, as well as extra "options", which include where to download a file to boot.
Client uses TFTP or HTTP to download a boot file. iPXE can handle multiple types of boot files, in your case it's an iPXE script.
Client runs this script to download the actual boot images. It could be ISO images, or kernel + initrd + NFS mount, or boot from iSCSI target.
This is just iPXE script syntax. First line sets a variable XXX, and the third line uses it ${XXX}. However, IMHO, they are bad names. According to "Dynamic Host Configuration Protocol Options Used by PXELINUX" 209 and 210 are DHCP options. 209 means "config file", and 210 means "path prefix".
So they mean certain things, but they are just names and can be named any other way.
Related
I have been using a Unix shell to download raw reads using sratoolkit/2.8.2-1. The SRA files are from the NCBI database e.g. for "https://www.ncbi.nlm.nih.gov/sra?term=SRX1157907". When I use the prefetch command (e.g. prefetch SRR2172947) consistently get the error of "path not found while resolving tree within virtual file system module - 'SRR2172948' cannot be found." I can download other SRA files like SRR12626663 without a problem, but the mentioned link has some problem.
Would it be possible to please guide me on how to solve this problem?
Human genomics data in NCBI's SRA is often under controlled access through the dbGaP system. One must request access to these files and follow special protocols to download such data. For example, researchers must demonstrate valid research needs to gain access approval and agree to follow protocols to ensure the data is securely stored.
I am using guacamole to connect to remote devices over RDP for Windows machines and SSH for Linux. Now I would like to enable SFTP support for the connections so I enabled the option 'Enable SFTP' in the guacamole connection settings.
The problem is SFTP is working for smaller files (<3KB), creates 0KB files for slightly larger files (3KB-150KB) and raises internal error for larger files (>150KB). I checked for what file size SFTP is failing by trial, transferring files of different sizes to the remote machine.
In the screenshot, it can be seen that 'attendance.py' a smaller file of size 548 bytes is successfully transferred to the tmp folder in the Linux machine, but the other two files files are created as empty files. The pdf file I tried to move is close to 180KB, which raises a Internal Error. I checked if there is some dependency with this error and filetype but this problem occurs for all file formats. I have the same problem when transferring file to a windows machine configured with RDP protocol in the same guacamole server.
Can someone help me with this? Thanks in advance
Are you using a reverse Proxy?
I had the same problem by using nginx. It seems it is by default not allowing files greater than 1MB.
I could change that at nginx to any size and now it works.
For nginx look for: client_max_body_size
If you are not using nginx, i would take a look at the webserver config. Remember, you using some sort of a webserver and a filelimit is there usualy very much needed.
I utilize the Apache VFS library to access files on a remote server. Some files are symbolic links and when we get the file size of these files, it comes back as 80 bytes. I need to get the actual file size. Any ideas on how to accomplish this?
Using commons-vfs2 version 2.1.
OS is Linux/Unix.
You did not say which protocol/provider you are using. However it most likely also does not matter: none of them implement symlink chasing as far as I know (besides local). You only get the size reported by the server for the actual directory entry.
VFS is a rather high level abstraction, if you want to commandeer a protocol client more specially, using commons-net or httpclient or whatever protocol you want to use gives you much more options.
I want to build a RabbitMQ cluster in my dev machine (windows).
reason is that I would like to test and study it.
Is it possible to run more than one rabbitmq instance on one machine?
I am guessing I need to:
Change the listening port
Change the appdata folder (C:\Users\MyUser\AppData\Roaming)
Change the ui plugin port so I can view all instances.
Remove the service and run from cli
Has anyone tried it?
Is there a known guide?
This thread appears to detail what you need. From the thread responses (scroll down):
The following settings are necessary to separate the node runtimes
completely, while allowing them to share the installed code base.
RABBITMQ_CONFIG_FILE /etc/rabbitmq/rabbitmq
RABBITMQ_MNESIA_BASE /var/lib/rabbitmq/mnesia
RABBITMQ_LOG_BASE /var/log/rabbitmq
RABBITMQ_ENABLED_PLUGINS_FILE /etc/rabbitmq/enabled_plugins
Now the official RabbitMQ documentation contains a section "A Cluster on a Single Machine", which describes how to run multiple Rabbit nodes on a single machine.
See https://www.rabbitmq.com/clustering.html#single-machine
One approach that I took when testing out clustering on my dev machine was to fire up several VMs. I had several for Rabbit and one for HAProxy.
While you can, as per one of the other answers, run multiple instances on a single OS instance, the multiple VM approach allowed me to mimic the intended production environment more closely.
NB. I have chosen to interpret your 'one machine' as meaning a physical machine for the purpose of this answer. If your meaning was 'virtual' then I defer to the other answer posted against this question which details how to accomplish this.
You can run multiple RabbitMQ instances on 1 machine without clustering. You just need to change the ports and the node name in rabbitmq-defaults, rabbitmq-env and config files.
For Linux:
Make sure you have Erlang installed, then download the latest version for Generic Unix and extract it.
Go to rabbit installation folder(the folder you just extracted)/sbin -> open the rabbitmq-defaults file and change SYS_PREFIX=${RABBITMQ_HOME} to create the default folder somewhere else, you should set the path to the extracted folder, for ex. /home/YOUR-USERNAME/rabbit_server-msg(this is my extracted folder).
Change the node name. Open the rabbitmq-env file -> find NODENAME=rabbit#${HOSTNAME} and change the name rabbit (ex. rabbitMSG#${HOSTNAME}). In the same file locate and change DEFAULT_NODE_PORT, by default it’s set to 5672. The default clustering port is set by ${DEFAULT_NODE_PORT} + 20000. So if you set the default node port to 5673, the clustering port will be 25673.
Install the Management Plugin. Navigate to rabbitmq-server/sbin and run “./rabbitmq-plugins enable rabbitmq_management”
The AMQP and HTTP ports need to be chnaged in the config file. Copy the file rabbitmq.config.example and paste it in the rabbit_server-msg(again this is my extracted forlder)/etc(this is the default folder created by RabbitMQ from step 1)/rabbitmq folder, rename the file to just rabbitmq.config. If you can’t find the file rabbitmq.config.example in the rabbit folder create a file named rabbitmq.config and copy the code from their GitHub.
Open the config file and uncomment the following lines:
– {tcp_listeners, [5672]} and change the port number (It is recommended to set the same number as the DEFAULT_NODE_PORT in rabbitmq-env for example 5673).
– {listener, [{port, 12345} and change the port number (This is for the management plugin).
NOTE: Be careful with the commas and brackets. Remove the comma after {tcp_listeners, [5672]}. Also after {listener, [{port, 12345} close the brackets like so ]}. Otherwise when you try to run ./rabbitmq-server it will show errors (It will show you on which line in the config file you have an error so you can fix it).
Now start up the server and log in the manager. Check the Listening ports under Ports and contexts to see if you made the changes. Do this for the other servers and you will be able to run as many servers as you want on 1 machine all with different listening ports. To start the RabbitMQ server automatically when you log in use the Startup Application program.
For Windows:
Setting up RabbitMQ for Windows is preatty much the same as on Linux.
Make sure you have Erlang installed, then download the latest version for Windows and extract it.
Go to rabbit(the folder you just extracted)/sbin -> open the rabbitmq-defaults.bat file and change RABBITMQ_BASE to create the default folder somewhere else, you should set the path to the extracted folder, for ex. C:/rabbit_server-msg(this is my extracted folder).
Change the node name. Open the rabbitmq-env.bat file -> find RABBITMQ_NODENAME=rabbit#!HOSTNAME! and change the name rabbit (ex. rabbitMSG#!HOSTNAME!). In the same file locate and change RABBITMQ_NODE_PORT, by default it’s set to 5672. To change the default clustering port locate and change RABBITMQ_DIST_PORT, by default it’s set to 25672.
Install the Management Plugin. Navigate to rabbit-server/sbin and run “rabbitmq-plugins.bat enable rabbitmq_management”.
The AMQP and HTTP ports need to be chnaged in the config file. Create a file named rabbitmq.config and copy the code from their GitHub. Put the file in your installation folder/RabbitMQ (ex. my config is in C:/rabbit_server-msg/RabbitMQ). Also in the rabbitmq-defaults.bat file check CONFIG_FILE it should be set to CONFIG_FILE=!RABBITMQ_BASE!\rabbitmq.
Open the config file and uncomment the following lines:
– {tcp_listeners, [5672]} and change the port number (It is recommended to set the same number as the RABBITMQ_NODE_PORTin rabbitmq-env for example 5673).
– {listener, [{port, 12345} and change the port number (This is for the management plugin).
NOTE: Be careful with the commas and brackets. Remove the comma after {tcp_listeners, [5672]}. Also after {listener, [{port, 12345} close the brackets like so ]}. Otherwise when you try to run rabbitmq-server.bat it will show errors (It will show you on which line in the config file you have an error so you can fix it).
Now start up the server and log in the manager. Check the Listening ports under Ports and contexts to see if you made the changes. Do this for the other servers and you will be able to run as many servers as you want on 1 machine all with different listening ports.
Source: https://lazareski.com/multiple-rabbitmq-instances-on-1-machine/
I have got dedicated server and file about 4 GB to upload on the server. What is the fastest and most save way to upload that file to the server?
FTP may create issues if the connection will be broken.
SFTP will have the same issue as well.
Do you have your own computer available through internet public IP as well?
In that case you may try to set up a simple HTTP server (if you have Windows - just set up the IIS) and then use some download manager on dedicated server (depends from OS) to download the file through HTTP (it can use multiple streams for that) or do this through torrent.
There're trackers, like http://openbittorrent.com/, which will allow you to keep the file on your computer and then use some torrent client to upload the file to the dedicated server.
I'm not sure what OS your remote server is running but I would use wget it has a --continue from the man page:
--continue
Continue getting a partially-downloaded file. This is useful when
you want to finish up a download started by a previous instance of
Wget, or by another program. For instance:
wget -c ftp://sunsite.doc.ic.ac.uk/ls-lR.Z
If there is a file named ls-lR.Z in the current directory, Wget
will assume that it is the first portion of the remote file, and
will ask the server to continue the retrieval from an offset equal
to the length of the local file.
wget binaries are available for GNU/Linux / Windows / MacOSX / dos:
http://wget.addictivecode.org/FrequentlyAskedQuestions?action=show&redirect=Faq#download