Has anyone used the lockfile utility that ships with procmail in conjunction with NFS mounted directories?
The lockfile man page states that "Lockfile is NFS-resistant and eight-bit clean."
I've used it. My company had an very NFS-intensive infrastructure at one point (less so now) and many Perl sysadmin tools dating back to the mid 90s. We wrapped lockfile in a perl module so that we could do consistent locking across NFS mounts. For that matter, our home directories were NFS mounted and we used procmail to deliver mail into them using the same style of locking and never had any problems with it (procmail delivering mail via NFS from server-a and mail being read via firect file access or UW-imap from a bunch of other servers).
Related
I am working on a project that requires using raw_sockets and raw sockets to work needs CAP_NET_RAW we used setcap and it worked fine, now the executable is on NFS, and nw setcap can’t be used is their a work around? Thanks in advance
I tried chown root and chmod u+s to increase prevelage of my executable but it didn’t work
Your app uses raw sockets, and raw sockets requires that the process have CAP_NET_RAW capability, correct?
https://manpages.ubuntu.com/manpages/kinetic/en/man7/packet.7.html,
In order to create a packet socket, a process must have the
CAP_NET_RAW capability in the user namespace that governs its network
namespace.
You've been relying on extended attributes to associate CAP_NET_RAW capability with your app's executable file, but your NFS server doesn't support this, correct?
Here's a potential workaround:
https://stackoverflow.com/a/44103544/421195
You can use fuse_xattrs (a
fuse filesystem layer) to emulate extended attributes (xattrs) on NFS
shares. Basically you have to do:
mount the NFS share. e.g.: /mnt/shared_data
mount the fuse xattr layer:
$ fuse_xattrs /mnt/shared_data /mnt/shared_data_with_xattrs
Now all the files on /mnt/shared_data can be accessed on
/mnt/shared_data_with_xattrs with xattrs support. The extended
attributes will be stored on sidecar files. The extended attributes
are not going to be stored on the server filesystem as extended
attributes, they are going to be stored in sidecar files.
Sadly this is only a work-around.
disclaimer: I'm the author of fuse_xattrs.
fbarriga
I am looking for JCL Script/Procedures in mainframe which can facilitate file transfer from Unix server to Mainframe.I am required to do FTPS for the Outbound Jobs (pull the file from UNIX server to mainframe Host).
Rather than a JCL, just do it a shell script. Here is a good site on using such commands:
https://blog.eduonix.com/shell-scripting/how-to-automate-ftp-transfers-in-linux-shell-scripting/
Once you have that working in the shell script in USS, you should be able to call the shell script from a JCL so you can execute it on a scheduled batch job if you need it.
Kenny's suggestion is fairly reasonable. IBM's documentation on how to write JCL for FTP(S)-related tasks is available in their "z/OS Communications Server: IP User's Guide and Commands" publication, IBM Publication No. SC27-3662. The current revision appears to be SC27-3662-30, but later revisions are possible. You can easily find this publication online, and make sure you don't skip the section beginning with the title "Submitting FTP requests in batch." Make sure you set the security options correctly (of course).
Please note that you're asking about FTPS, i.e. TLS encryption applied to either or both (preferably both) of the FTP channels (control and data). SFTP is another file transfer protocol based on SSH that z/OS also supports.
Another possible approach that you'll fairly often find available on z/OS installations is to use IBM MQ Advanced for z/OS's Managed File Transfer (MFT) feature to retrieve the file(s) using FTPS. As the name suggests, this'll be managed and have at least some error handling capabilities.
Yet another possible approach if you prefer HTTPS protocol is to use the z/OS Client Web Enablement Toolkit's HTTPS protocol enabler to fetch the file. That's a built-in, standard feature in all currently supported z/OS releases, and you can use it from a relatively simple REXX script for example. Details are available here (z/OS 2.3 variant of the documentation):
https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.ieac100/ieac1-cwe-http.htm
We have a IBM Host System Z sitting in our cellar. Now the issue is that i have no clue about Mainframes!!! (It's not USS btw.)
The Problem: How can i transfer a file from the host system to a windows machine.
Usually on UNIX systems i would just install and ssh daemon and connect to it via. a program called winscp. After that transfer the file in binary so that it does not convert something (Ultraedit and other Editors can handle this).
With the host system it seems to be a bit difficult as the original format from IBM is EBCDIC and i have no idea if there is a state of the art SFTP server program for the host. Could anybody be so kind and enlighten me? From my current expirience with IT there must be a state of the art sftp connection to that system? I appreciate any help/hints/solutions.
Thank you,
O.S
If the mainframe "sitting in [your] cellar" is running z/OS then it has Unix System Services installed. You can't have z/OS without it.
There is an SFTP package available (for free) for z/OS.
You can test to see about Unix System Services by firing up a 3270 emulator going to ISPF option 3.17, putting a forward slash (/) in the Pathname field and pressing the mainframe Enter key. Another way would be to key OMVS at a TSO READY prompt, which will start up a 3270-based Unix shell.
It is possible that USS is simply not available to you; if you're running any supported release of z/OS then USS is present. There could be concerns about supporting something outside a particular group,
Or, depending on what OS you have running on your System z, it's possible you don't have z/OS. You could have z/VM, you could have zLinux, you could have TPF. However, if you're running zLinux, you have linux, which has sftp installed, and which uses ASCII, not EBCDIC.
As cschneid says, however, if you have z/OS, you have USS. TCP/IP, among other things, won't run without it. Also note that z/OS TCP/IP has an FTP server, so you can connect that way if the FTP server is set up. If security is an issue, FTPS is supported, although it's painful to set up. With the native FTP server, you can convert from EBCDIC to ASCII when you're doing the transfer. There's also an NFS server available. And SMB as well, I believe.
And there's an FTP client available as well, so you could FTP from z/OS to your system, if you wanted to.
Maybe a better thing to do would explain what you're trying to do with the data, and what the data is, in general. You can edit files directly on the mainframe, using either TSO, ISPF, or OMVS editors. There are a lot of data types that the mainframe supports that you're not going to be able to handle on a non-z system unless you go through an export process. I'm not really clear on whether you want to convert the file to ASCII when you transfer it or not.
While the others are correct that all recent releases of z/OS have USS built-in, there's quite a bit of setup work that needs to be done in order for individual users to have access to USS capabilities like SFTP. Out of the box, you get USS "minimal mode" that just has enough of USS to support the TCP/IP stack and so forth. USS "full function mode" requires setup:
HFS filesystems need to be allocated
Your security package needs to be manage UIDs/GIDs for your users
etc etc etc
Still, with these details and with nothing more than the software you're entitled to as part of your z/OS license, you can certainly run SFTP and all the other UNIX style network services you're used to.
A good place to start is the UNIX Services Planning guide: http://publibz.boulder.ibm.com/epubs/pdf/bpxzb2c0.pdf
So, I've taken a handful of programming courses(object-oriented, web) but never had "hands-on" projects where it's outside of coding.
Now I'm trying to figure out what these SSH stuff is about, I can't even figure out which client to use, so picked filezilla for now.
My question is, where can I read more about these terms like ports, and whatnots, in a way so I'm not learning aimlessly.
Thanks!
Basically, SSH is a way to command another computer exactly what to do over the Internet. You can execute any commend the remote system has, and your user has permission for.
The Internet
The Internet runs on a series of protocols collectively named TCP/IP. TCP/IP defines a way to find and address individual computers (IP) and a way to communicate between them (TCP).
You can think of computers on the Internet as a large collection of office buildings all close together. Each office has the exact same number of windows: 65535. Offices (computers) communicate by stringing channels between windows (ports). Each channel has two ends, called sockets. Each socket is associated with a port on the respective computer. We send data back and forth, and then the connection is closed.
Client/Server
There are two types of computers on the Internet: clients, and servers. Clients request information, and servers provide it. Ports 1-1024 are reserved for servers, 1 port per protocol. The full list is here, and as you can see, it is not without contention.
Let's say you visit a website
Your browser, the client program, sees that you typed "stackoverflow.com", and using DNS, discovers that stackoverflow.com is computer number 64.34.119.12. This is it's IP address. It allows your computer to find the network stackoverflow.com is located in, route to it, and establish a connection to the Stack Overflow web server. The web server is a program that accepts client requests from a browser like yours.
They speak in a protocol called HTTP - it allows your browser to request a page determined by a URL. The server sees the request, runs a program to construct a web page (or retrieves an HTML file, image, or any other file), and sends the result back to the browser. Port 80 has been reserved for HTTP. That means, your computer chooses a random port to connect from, and connects to port #80 on the server.
Unix and the shell
The majority of the Web (The Internet, even) runs on an OS called Linux (a Unix variant), instead of something like Windows. Unix systems possess a command-line interface, running a program called a "shell", which is a direct interface to the system. The shell accepts input, one command at a time. You type text in, and it spits out the out put of the command.
Secure Shell
SSH allows you to do this securely. All data traffic is encrypted using a well-studied published "public-key" cryptographic system. (In fact, it was major news when a vulnerability was discovered in a supporting encryption scheme, see these advisories).
SSH is a protocol commonly running on port 22. Anyone with a computer on the Internet (not behind a firewall) can run an SSH server, and allow users to connect to it and execute commands.
The majority of systems administrators and software developers using Unix on the server use SSH to configure, control, and upload programs to that server (located in some data center somewhere).
More
There are many many more details to all of this. Any term or acronym above can be typed into Wikipedia for pretty comprehensive information. There are plenty of books on Unix, Networking, and Web programming.
SSH is originally a secured replacement for telnet. The need for SSH arose from the fact that telnet does not support encryption and therefore everything (commands, output and password) was plainly visible on the network for all to see.
Because in the beginning SSH encryption (based on key exchange) was supposed to be strong (and it was indeed a marked improvement), and was open source, it took off rapidly and several extensions to the protocol were added, especially in the domain of remote file manageent and transfer.
In addition, SSH is used in tunelling and port forwarding configurations.
In the domain of file copy there are several options.
SCP: cp (copy). Inspired by rcp, an early file transfer extension to ssh.
SFTP: SSH File Transfer Protocol, a newer SSH extension to support File copy and browsing (but not really like FTP with 2 ports). It is more feature rich than both scp and ftp. Think of it as a remote file system protocol (however, however somewhat slower than scp).
FTPS: FTP over TLS/SSL. Needs 2 ports like ftp, one for command and one for data. Both connections can be encrypted.
Secure FTP. Real FTP tunelled over SSH.
The site to which you will need to connect probably offers SFTP. You just need to declare the remote server connection configuration in Filezilla site manager. You will need to provide the server ip address or name, the SSH server port, usually 22 but there are other possibilities (you should have been provided with this info) and select sftp as server type). When the connection is established, accept the public key and that should be it.
You can then drop your devs on the remote server.
OS choice
You shall first make a kind of choice between 2 worlds (MS or Linux).
Provided that the Linux community is somehow significantly less reluctant to share explanations. Also you will loose less time by choosing one or the other one, avoiding to wonder the same questions twice, with different answers depending on which OS you chose.
I experienced both, starting to search for solutions in the MS world, that I knew. Big mistake, loss of time. Then I changed, too late, to the Linux world. So I would advice to go straight to the linux OS for learning. Really many distributions for this. I would advice Debian (opened, user friendly, simple, safe, huge community) but you'll get as many proposals as there are admin.
OS understanding
http://www.linuxfromscratch.org/lfs/
http://www.ibm.com/developerworks/library/l-bash.html
http://tldp.org/LDP/abs/html/
Specific Questions about SSH
It depends a lot on the system you will choose but you could easily build a small client and a small server, then configure both and use ssh. Your 2 servers could even be hosted on the same machine, locally if you wish. Then you will learn how to set up the ssh-client side (often called ssh_config) and the ssh server side (often named sshd_config, with "d" standing for daemon).
Here you can find explanations about ssh for both worlds :
http://support.suso.com/supki/SSH_Tutorial_for_Linux
Some keywords for your google searches
List_of_TCP_and_UDP_port_numbers
ssh-keygen : encrypted keys (private/public),
ssh-add ssh agent
Gentoo keychain
and later but soon if you administrate your server on your own
The two main ones :
1) iptables
You may start with this and then go further with that one
2) fail2ban
this is a complement tool for which you'll find easily plenty of docs
...
Have fun :-)
EDIT: you can easily experience a Linux machine hosted in a windows OS, using virtualization (virtualbox, vm-ware..). It's a safe start and offer a good payback for this time investment. It would allow you to host as many machines (for example one linux server and one linux client) as you wish, in the limits of your HD room.
I assume you need to learn shell scripting. I recommend this book.
Filezilla is a FTP client. Try Putty - free SSH Client. And of course you need Linux server.
If you want to learn about SSH in depth then may I advise you this book SSH: The Secure Shell The Definitive Guide
See here for more info: http://www.snailbook.com/
I've read the book and learned really a lot. It teaches you all about setting up servers, clients, key agents and various (practical) applications.
What is the easiest way to manage the authorized_keys file for openssh across a large number of hosts? If I need to add or revoke a new key to an account on 10 hosts say, I must login and add the public key manually, or through a clumsy shell script, which is time consuming.
Ideally there would be a central database linking keys to accounts#machines with some sort of grouping support (IE, add this key to username X on all servers in the web category). There's fork of SSH with ldap support, but I'd rather use the mainline SSH packages.
I'd checkout the Monkeysphere project. It uses OpenPGP's web of trust concepts to manage ssh's authorized_keys and known_hosts files, without requiring changes to the ssh client or server.
I use Puppet for lots of things, including this.
(using the ssh_authorized_key resource type)
I've always done this by maintaining a "master" tree of the different servers' keys, and using rsync to update the remote machines. This lets you edit things in one location, push the changes out efficiently, and keeps things "up to date" -- everyone edits the master files, no one edits the files on random hosts.
You may want to look at projects which are made for running commands across groups of machines, such as Func at https://fedorahosted.org/func or other server configuration management packages.
Have you considered using clusterssh (or similar) to automate the file transfer? Another option is one of the centralized configuration systems.
/Allan