Linux x64

CloudCaptain supports Linux x64 apps packaged as a tar.gz.


Applications should be packaged as a tar.gz file and include all necessary dependencies.

To minimize the complexity of the package, try to compile your application as a statically linked binary.

You can specify the command to launch using the cmd argument. This should include the relative path to binary as well as all necessary arguments:

> boxfuse run my-linux-x64-app-1.2.3.tar.gz "-cmd=bin/myapp -with -my args"

If the don't specify a command, CloudCaptain will automatically pick the first executable file in the tar.gz and run it without arguments.

Root Certificates

CloudCaptain uses the same root certificate bundle as the latest version of Firefox. Additionally CloudCaptain also includes the root certificates for Amazon RDS, so you can connect securely to RDS databases out of the box.

Temporary Files

CloudCaptain configures the instance to use /tmp as the directory to store temporary files and provisions 1 GB of space by default.

To increase this (up to a maximum of 16 TB), simply set the tmp configuration setting to the number of GB of temp space you need. To prevent CloudCaptain from provisioning any temp space set tmp to 0.

Time Zone

By default all CloudCaptain instance use the UTC time zone.

We don't recommend changing this as this greatly simplifies time zone issues in machine to machine communication and cleanly relegates all time zones related aspects to a pure presentation layer concern.

If however you still do want to change this, you can override the default time zone of the instance using the TZ environment variable. For example to change the time zone of your instance to America/Los_Angeles you would do so like this:

> boxfuse fuse -envvars.TZ=America/Los_Angeles

Linux Kernel Tuning (experts only)

Kernel arguments

To tune the arguments passed Linux kernel from the bootloader, simply pass them using the -linux.args setting when fusing your image.


If you need to tune the Linux kernel running in your instance, simply place a sysctl.conf file at the root inside your tar.gz file.

You can then for example tune the maximum number of file descriptors by simply including the following in sysctl.conf:

fs.file-max = 131072

CloudCaptain will then automatically configure the Linux kernel to use these settings.