Fine tuning your Cloud Setup
OverviewTeaching: 5 min
Exercises: 10 minQuestions
Is my remote computer correctly configured?
How do I keep my processing going when I leave?Objectives
Check the available resources and file system on your remote machine
Keep background processes working in the cloud with
Is this the right cloud?
Once you’re connected to your new remote instance, it’s a good idea to double check that the settings are what you wanted, and that everything is working smoothly before you start your project.
For this workshop, your instructor did all the verification before the workshop even started, but this is an important skill for when you start running your own instances.
Verifying your connection
When you connect, it is typical to receive a welcome screen. The Data Carpentry Amazon instances display this message upon connecting:
Welcome to Ubuntu 14.04.3 LTS (GNU/Linux 3.13.0-48-generic x86_64) * Documentation: https://help.ubuntu.com/ System information as of Tue Jan 29 22:28:18 UTC 2019 System load: 0.04 Processes: 164 Usage of /: 43.1% of 98.30GB Users logged in: 0 Memory usage: 2% IP address for eth0: 172.31.41.107 Swap usage: 0% Graph this data and manage this system at: https://landscape.canonical.com/ Get cloud support with Ubuntu Advantage Cloud Guest: http://www.ubuntu.com/business/services/cloud New release '16.04.5 LTS' available. Run 'do-release-upgrade' to upgrade to it.
You should also have a blinking cursor awaiting your command
Verifying your environment
Now that we have connected here are a few commands that tell you a little about the machine you have connected to:
whoami- shows your username on computer you have connected to:
dcuser@ip-172-31-62-209 ~ $ whoami dcuser
df -h- shows space on hard drive
dcuser@ip-172-31-62-209 ~ $ df -h Filesystem Size Used Avail Use% Mounted on udev 2.0G 12K 2.0G 1% /dev tmpfs 396M 792K 395M 1% /run /dev/xvda1 99G 48G 47G 51% / none 4.0K 0 4.0K 0% /sys/fs/cgroup none 5.0M 0 5.0M 0% /run/lock none 2.0G 144K 2.0G 1% /run/shm none 100M 36K 100M 1% /run/user
Under the column ‘Mounted on row’ that has
/as the value shows the value for the main disk
cat /proc/cpuinfo- shows detail information on how many processors (CPUs) the machine has
dcuser@ip-172-31-62-209 ~ $ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 62 model name : Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz stepping : 4 microcode : 0x415 cpu MHz : 2494.060 cache size : 25600 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology eagerfpu pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm xsaveopt fsgsbase smep erms bogomips : 4988.12 clflush size : 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 62 model name : Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz stepping : 4 microcode : 0x415 cpu MHz : 2494.060 cache size : 25600 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 apicid : 2 initial apicid : 2 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology eagerfpu pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm xsaveopt fsgsbase smep erms bogomips : 4988.12 clflush size : 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual power management:
tree -L 1- shows a tree view of the file system 1 level below your current location.
dcuser@ip-172-31-62-209 ~ $ tree -L 1 . ├── dc_sample_data ├── Desktop ├── Downloads ├── FastQC ├── openrefine-2.6-beta.1 ├── R └── Trimmomatic-0.32 7 directories, 0 files
Staying Connected to the Cloud
Depending on how you connect to the cloud, you may have processes and jobs that are
running, and will need to continue running for some time. If you are connecting to your
cloud desktop via VNC, jobs you start will continue to run. If you are connecting via SSH,
if you end the SSH connection (e.g. you exit your SSH session, you lose your connection
to the internet, you close your laptop, etc.), jobs that are still running when you
disconnect will be killed. There are a few ways to keep cloud processes running in the background.
Many times when we refer to a background process we are talking about what is
described at this tutorial -
running a command and returning to shell prompt. Here we describe a program that will
allow us to run our entire shell and keep that process running even if we disconnect:
tmux. If you don’t have
tmux on your system, you should still be able to use
screen. This is another program that has mostly the same capabilities as
tmux. It’s a lot older, though, so can be more clunky to use; however, it is likely to be available on any cloud system you encounter.
screen, you open a ‘session’. A ‘session’ can be thought of as a window for
screen, you might open an terminal to do one thing on the a computer and then open a new terminal to work on another task at the command line.
As you work, an open session will stay active until you close this session. Even if you disconnect from your machine, the jobs you start in this session will run till completion.
Starting and attaching to a session
You can start a session and give it a descriptive name:
$ tmux new -s session_name
$ screen -S session_name
This creates a session with the name
session_name which will stay active until you close it.
Detach session (process keeps running in background)
You can detach from a session by pressing on your keyboard:
control + bfollowed by
control + afollowed by
Seeing active sessions
If you disconnect from your session, or from your ssh into a machine, you will need to reconnect to an existing session. You can see a list of existing sessions:
$ tmux list-sessions
$ screen -ls
Connecting to a session
To connect to an existing session:
$ tmux attach -t session_name
-toption = ‘target’
$ screen -r session_name
-roption = ‘resume a detached screen session’
You can switch between sessions:
$ tmux switch -t session_name
Kill a session
You can end sessions:
$ tmux kill-session -t session_name
$ screen -r session_name $ exit
Installing additional software
tmux is not installed in most cloud Linux instances. However you can install new software packages using Package Managers like YUM (for Red Hat and Centos instances) or APT (for Debian or Ubuntu instances). We will explore how to install
tmux using APT (Advanced Package Tool).
Before installing or upgrading any system packages, you should always update the local APT cache:
$ sudo apt-get update Hit:1 http://au.archive.ubuntu.com/ubuntu xenial InRelease Get:2 http://au.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB] ... Fetched 3,413 kB in 1s (2,233 kB/s) Reading package lists... Done
Search for APT packages using including software
Most common software tools will have a package named the same, but this is not always the case. If you know the name of the program you wish to install, but are not sure of the package name, you can use the
apt program to search packages:
$ sudo apt search tmux Sorting... Done Full Text Search... Done abduco/xenial 0.1-2 amd64 terminal session manager powerline/xenial-updates 2.3-1ubuntu0 amd64 prompt and statusline utility tmate/xenial 1.8.10-2build1 amd64 terminal multiplexer with instant terminal sharing tmux/xenial,now 2.1-3build1 amd64 terminal multiplexer tmuxinator/xenial 0.7.0-2 all Create and manage tmux sessions easily $
There is a plain
tmux package, so we will use that to install.
Install packages using APT
Once you know the package name, you can install it using
$ sudo apt-get install tmux Reading package lists... Done Building dependency tree Reading state information... Done The following additional packages will be installed: libevent-2.0-5 libutempter0 The following NEW packages will be installed: libevent-2.0-5 libutempter0 tmux 0 to upgrade, 3 to newly install, 0 to remove and 0 not to upgrade. Need to get 345 kB of archives. After this operation, 949 kB of additional disk space will be used. Do you want to continue? [Y/n] y Get:1 http://mirror.overthewire.com.au/ubuntu xenial-updates/main amd64 libevent-2.0-5 amd64 2.0.21-stable-2ubuntu0.16.04.1 [114 kB] Get:2 http://mirror.overthewire.com.au/ubuntu xenial/main amd64 libutempter0 amd64 1.1.6-3 [7,898 B] Get:3 http://mirror.overthewire.com.au/ubuntu xenial/main amd64 tmux amd64 2.1-3build1 [223 kB] Fetched 345 kB in 0s (863 kB/s) (Reading database ... 130583 files and directories currently installed.) ... Setting up libevent-2.0-5:amd64 (2.0.21-stable-2ubuntu0.16.04.1) ... Setting up libutempter0:amd64 (1.1.6-3) ... Setting up tmux (2.1-3build1) ... Processing triggers for libc-bin (2.23-0ubuntu10) ...
When this has completed,
tmux will now be available for use on the instance.
Always check a new instance to verify it started correctly
Using a program like
tmuxcan keep your work going even if your internet connection is bad