HOW TO SET UP APK MULTI TOOL FULL

The default shell in Alpine is the busybox provided ash.

If you’ve written Alpine Dockerfiles, you should already know apk pretty well. If you’re already familiar with the apt package manager, there’s no getting used to apk: the basic commands are add, del, search, and update, and you’re good to go.

A neat and simple package manager called apk.

Consequently, Linux executables that were built on glibc distros such as Ubuntu and RedHat, will not be able to run on Alpine, at least not out of the box. Almost any Linux program is dynamically linked with libc, and while glibc Linux binaries will link against libc.so, Alpine binaries will link against musl.so. This comparison chart from ETA labs, authors of musl, gives a very detailed picture of the differences between the libc implementations and highlights musl’s strengths.īut, there’s a catch: having musl as the default libc implementation introduces a major compatibility issue with other Linuxes that are based on glibc. But, there’s much more to musl than its small size: it offers stricter POSIX conformance, improved safety, and competitive performance. Compared to glibc, musl is tiny in size: it weighs only 572 KB on Alpine 3.8, compared to glibc’s 3 MB on Ubuntu 16.04, for example (3 MB is the combined size of libc.so and libm.so in Alpine, libm.so is symlinked to musl.so). The musl libc library is a compact and compelling alternative to GNU’s libc library, glibc, which is the defacto libc implementation used in most Linux distributions. On Alpine 3.8, it is squeezed into just 780 KB of goodness.

HOW TO SET UP APK MULTI TOOL FULL

It offers high compatibility to the GNU counterparts, typically with a reduced feature set, but worry not – you can usually get the full GNU functionalities by installing the package of the same name, such as grep or tar, or bundle packages like coreutils.īusybox is significant to Alpine’s small size – using a single static binary reduces the overhead of multiple executables and allows the resulting binary to be effectively size optimized. All programs are symlinked to /bin/busybox, which identifies the program to run according to the name it was executed with. Named by its authors “The Swiss Army Knife of Embedded Linux”, it provides the core functionalities for dozens of standard programs, such as awk, cp, grep, gzip, sh and top. Busybox is an all-in-one, multi-purpose binary. It is built around two components that make it especially compact: So, Alpine is as secure as it can be, but its small footprint is what really sets it apart from the other Linuxes.

Unfortunately, as with any other system, it is not 100% bulletproof. Though not a feature per se, Alpine’s minimalistic nature also makes it safer and less prone to attacks, since it carries little to no excess baggage and therefore the possible attack surface is much smaller, especially compared to other Linuxes. These are compiler generated variables that mark the end of the allocated stack frame in each function, and when overridden, indicate that the stack has overflowed and trouble is ahead, much like “canaries in a coal mine”. It is typically implemented by building with a special C/C++ compiler option ( -fstack-protector-fstrong), that adds stack canaries to the program code. This feature is implemented in all Alpine binaries, and allows stack overflowed programs to exit gracefully instead of crashing horribly.

Such executables are subject to Address Space Layout Randomization (ASLR), a technique in which the kernel dynamically shifts programs between random memory locations, which is useful for preventing certain kinds of attacks. All Alpine executables are built as PIE – Position Independent Executables -which do not depend on absolute memory addresses for their correct operation, much like shared libraries. The most notable security feature is a hardened, specially patched Linux kernel. The project homepage summarizes it nicely: “Alpine Linux is an independent, non-commercial, general purpose Linux distribution designed for power users who appreciate security, simplicity and resource efficiency.” So What Do You Get With Alpine Linux?įirst, let’s take a glimpse of the main features of Alpine Linux. In this post, I’ll cover my experience in setting up an Alpine Linux workstation for C++ and Java development, with some hopefully useful Alpine know-hows, tips and resources. That fact makes it an ideal choice as the base system of Docker images, where small size is desirable, and specifically for OpenJDK Docker images that otherwise take up several hundred MBs. Originally designed for routers, it is a secure, fast, feather-light Linux: a basic Alpine base image takes as little as 5 MB, orders of magnitude less than other popular Linux distros. Alpine Linux has gained great popularity in recent years and is probably the most favored Linux for Docker.

How to set up apk multi tool