SSHFS: Super Easy File Access over SSH
As you can see from the above examples, I needed to type my password to complete the SSH connection to the remote system. This can be eliminated by creating a trust relationship between the local and remote user accounts. This is not appropriate in all situations, because it essentially makes the accounts equivalent from a security perspective. Any malicious activity on one account can spread to other systems via the trust, so take caution and fully understand the implications of setting up trust relationships. To begin setting this up, you need to create an SSH key pair, which consists of public and private key files named id_rsa and id_rsa.pub, respectively.
The public key is copied to the remote system and placed in the $HOME/.ssh/authorized_keys file. Some systems may use the filename authorized_keys2 in addition to or instead of authorized_keys.
This allows any user in possession of the private key to authenticate without a password. We create the key pair using the command ssh-keygen. The files are placed in the proper locations automatically on the local system in the $HOME/.ssh directory. Because we already have my remote home directory mounted, appending the public key to the authorized_keys file is extra easy. Below are all the steps required (assuming you created the equivalent of the randombox_home directory and mounted it):
$ cd $HOME $ ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/home/matt/.ssh/id_rsa): <ENTER> Enter passphrase (empty for no passphrase): <ENTER> Enter same passphrase again: <ENTER> Your identification has been saved in /home/matt/.ssh/id_rsa. Your public key has been saved in /home/matt/.ssh/id_rsa.pub. The key fingerprint is: fa:e7:7c:e1:cb:7b:66:8b:67:07:05:99:7f:05:b9:4a matt@myworkstation $ mkdir randombox_home/.ssh $ chmod 700 randombox_home/.ssh $ cat .ssh/id_rsa.pub >> randombox_home/.ssh/authorized_keys $ chmod 600 randombox_home/.ssh/authorized_keys
In the above example, we create the key pair with an empty passphrase, then append the public key to the authorized_keys file in the remote home directory and set the permissions. After this is done, I no longer need to type the password when connecting to the remote account. To test this, first we unmount the remote home directory with the following command:
$ fusermount -u randombox_home
To test the trust relationship, we can try to run the uptime command on the remote system:
$ ssh firstname.lastname@example.org uptime 12:20:40 up 38 days, 4:12, 0 users, load average: 0.11, 0.04, 0.01
Good, no password needed. The trust relationship is working properly. If you have trouble getting this trust relationship to work, check the permissions on the files in .ssh on both systems. Many times lax permissions prevent SSH from using key files. Also, take a look at the syslog log files. OpenSSH's sshd server logs messages into syslog, which often are helpful in diagnosing key file problems. You may have to increase the logging verbosity level in the sshd_config file, usually found in /etc/ssh/.
You also can debug the connection by running ssh in the above example with the -vvv option to turn up verbosity. Now, let's mount the remote directory again. This time it does not prompt for my password:
$ cd $HOME $ mkdir randombox_home $ sshfs email@example.com: randombox_home $ ls -l randombox_home/ -rw-r----- 1 matt users 7286 Feb 11 10:33 sshfs.article.main.txt drwx------ 1 matt users 2048 Mar 21 2001 projects drwx------ 1 matt users 2048 Dec 1 2000 Mail drwxr-xr-x 1 matt users 4096 Jun 8 2002 public_html
In the last example, we configured and automated non-interactive mounting of a remote directory. Because we're no longer being prompted for a password, we can integrate SSHFS mounting into scripts, or better yet the GNOME desktop. To configure GNOME to mount our remote home directory automatically, we configure the SSHFS mount command as a session startup program. This is done from inside the Sessions preferences dialog. Navigate to Desktop→Preferences→More Preferences→Sessions->Add, and fill in the dialog as shown in Figure 1.
Upon the next login, GNOME automatically mounts the remote directory for me, as you can see in Figure 2.
Note that GNOME does not reliably kill this command upon exiting the session. You can unmount the remote directory manually using the fusermount -u randombox_home command. Another option is to automate the unmount by modifying the $HOME/.Xclients-default file to run the fusermount command as follows:
#!/bin/bash # (c) 2001 Red Hat, Inc. WM="gnome-session" WMPATH="/usr/bin /usr/X11R6/bin /usr/local/bin" # Kludged to run fusermount upon gnome logout. 20060301-MEH for p in $WMPATH ; do [ -x $p/$WM ] && $p/$WM; fusermount -u randombox_home; exit 0 done exit 1
Be aware that the .Xclients-default file is rewritten every time you run the switchdesk utility. You have to modify this file every time you use use the switchdesk utility to change your default desktop windowing manager.
Finally, you can add the appropriate sshfs commands in the boot startup file that is appropriate for your distribution. This way, your system will mount all the SSHFS directories automatically each time you boot your desktop.
Fast/Flexible Linux OS Recovery
On Demand Now
In this live one-hour webinar, learn how to enhance your existing backup strategies for complete disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible full-system recovery solution for UNIX and Linux systems.
Join Linux Journal's Shawn Powers and David Huffman, President/CEO, Storix, Inc.
Free to Linux Journal readers.Register Now!
|Fancy Tricks for Changing Numeric Base||May 29, 2016|
|Working with Command Arguments||May 28, 2016|
|Secure Desktops with Qubes: Installation||May 28, 2016|
|CentOS 6.8 Released||May 27, 2016|
|Secure Desktops with Qubes: Introduction||May 27, 2016|
|Chris Birchall's Re-Engineering Legacy Software (Manning Publications)||May 26, 2016|
- Tips for Optimizing Linux Memory Usage
- Working with Command Arguments
- Secure Desktops with Qubes: Introduction
- Secure Desktops with Qubes: Installation
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- CentOS 6.8 Released
- The Italian Army Switches to LibreOffice
- Linux Mint 18
- Fancy Tricks for Changing Numeric Base
- Chris Birchall's Re-Engineering Legacy Software (Manning Publications)
Until recently, IBM’s Power Platform was looked upon as being the system that hosted IBM’s flavor of UNIX and proprietary operating system called IBM i. These servers often are found in medium-size businesses running ERP, CRM and financials for on-premise customers. By enabling the Power platform to run the Linux OS, IBM now has positioned Power to be the platform of choice for those already running Linux that are facing scalability issues, especially customers looking at analytics, big data or cloud computing.
￼Running Linux on IBM’s Power hardware offers some obvious benefits, including improved processing speed and memory bandwidth, inherent security, and simpler deployment and management. But if you look beyond the impressive architecture, you’ll also find an open ecosystem that has given rise to a strong, innovative community, as well as an inventory of system and network management applications that really help leverage the benefits offered by running Linux on Power.Get the Guide