In this article, we will illustrate some of the most common handy commands to manage your server via SSH terminal as the platform allows establishing SSH access to any container on your account.

There are two ways to connect your server inside Jelastic PaaS over SSH:

SSH Gate - Based on preliminary generated SSH keys pair (where the public key should be added to your Account Settings, and the corresponding private key, handled at your local machine), you can connect to your server via any preferred local SSH client.

In this article, we will leverage the inbuilt Web SSH tool (to keep it simple and for quick access). Anyhow, the commands described below can be used similarly when working via a remote local client.

Important!:

We believe it is worth mentioning that the information provided in this section is rather for newbies than for an average developer, so you can skip it and proceed to more complex operations.

After entering the required container via console, you will get to the server home directory by default (commonly dedicated to storing your custom data and configs). The cd command is used, with the following available arguments to navigate amongst the folders:

Consequently, the violet string next to the container hostname will change, indicating your current location.

Important!: If you are new to a stack runtime that your instance runs, most likely you would like to explore its inner structure first (e.g. tree of files & directories, available configuration files, etc). The most convenient way is to use the inbuilt Jelastic File Manager GUI (available when you click on Config next to the required server at your developer?s panel as shown below):

You may see the appropriate file tree in a dedicated tab below.

1- To create a new file or folder, execute the commands below:

where

{file} and {dir} - the preferred file or folder name (if being created in the current directory)

[path-to/] - optional parameter for the case, this new item should be placed in a different location.

2- Use the command below to get the list of comprised files and directories at the current location (to ensure that the file and folder above have been actually created):

ls

3- Among the rest of the most common commands intended for file management, we need to mention:

Next, we will illustrate the default shell possibilities to monitor and manage your node?s metrics like resource consumption, running inside processes, etc.

1- Use the w command to get a short summary of the current container state and ensure that, for example, no malefactor affects its performance and/or operability :

The output will provide you with some general system information in a header (namely - current system timestamp, instance uptime, number of logged users, and the average amount of active processes for the last 1/5/15 minutes) and details about the connected users below (their names, terminal type, source connection IP, login time, stats on the last activity and name of the currently active process(es), run on behalf).

Important!: The w command output does not include information on users, connected via a terminal emulator, due to the native shell implementation specifics.

2- All statistics on server RAM usage are stored within the /proc/meminfo file. Use the mentioned above cat command, to review the content:

cat /proc/meminfo

Here, you can also check several data such as total memory allocated (MemTotal), unused memory (MemFree), memory used as a cache (Cached), and more.

3- Execute the following command line to display the basic software and hardware container data :

uname -a

There you can see info on a server kernel (name, version, release date), node hostname, CPU type, OS, etc.

1- You can monitor all running processes inside a container with the top command while connected over SSH:

The information shown is constantly updated in a real-time mode, displaying info on all user?s processes (including system ones).

Press Ctrl + C to terminate the command execution and return to the console input mode.

2- Type in ps and run this command to display only your user?s active processes:

3- Kill is another command that allows terminating any running process, designated by its {pid} as an argument (the required process identifier can be found in the previous command?s output):

kill {pid}

You will notice that the run process, shown on the screen within the 2nd step of this section, was stopped because it is not listed among the active ones for now.

You can fetch the necessary files from the Internet (e.g., your application archive) directly through the console, to store and/or deploy them within your server.

1- The wget command allows downloading files by the specified {link}:

wget {link}

2- Next, you can unzip the downloaded archive with the same-named command:

unzip {archive}

where {archive} is a path to your compressed package.

Consequently, all extracted files will be placed in a same-named (after the archive) folder inside the current directory.

1- You can check the list of default environment variables for any container within the .bash_profile file. It is located in the container?s home directory. Firstly, ensure that you have got the proper container directory and execute the next command:

cat .bash_profile

2- By default, the .bash_profile file is not editable, so if you need to additionally set your own variables, write them down to the .bashrc file within the same folder (just create it, if missing). To finalize this, use any preferable text editor (e.g., vi):

3- Here, new variables should be defined in the following format:

export {VAR_NAME}={VAR_VALUE}

where:

Important!: The changes will be automatically applied when starting all further user sessions as the .bashrc file is read during the bash initiation. If you need to apply the made changes immediately, run the bash command to restart the shell.

4- Execute the command as below if you want to check whether your custom variable was successfully applied:

echo ${VAR_NAME}

You can see the {VAR_VALUE} string similar to the value you have just assigned to the ${VAR_NAME} variable in the .bashrc file.

At Jelastic PaaS, there are 2 types of software stack templates, used as a base when creating each of the containers:

You will be logged in as a default server user by entering the server via SSH. In addition, you can also execute some additional options under a regular user account to increase the effectiveness of container management:

Despite being run in a sudo mode, any of the commands above do not require entering server admin root password. By so, you to take advantage of all the required container functionality even with regular account permissions.

As you know all the required basics to manage your containers via console, you can leverage even more PaaS flexibility while running your applications.