Docker images are copied, transmitted, and launched by container fleet managers.

If not, getting something to work on Alpine may just not be worth it Might you have any citation(s) for this? not being able to get into the container does pose a big advantage. To be honest, I rarely use base images myself. As far as I can tell, the recommended way to run several processes in an Ubuntu container is under supervisord. The answer is simple: for performance and security. Sometimes they can contain excess binaries you dont need, and they dont have the ones you do need which can break your runtime dependencies. For example a minicon analysis existing in containers gives some hints, for instance the RUN commands and other commands that will be required, and based on that, hints are able to significantly reduce the image size of the container. java runtimes can expose debugging ports when needed that operate on a custom protocol. Change), You are commenting using your Facebook account. Maybe not as minimal as Alpine, but not heavy either. Even if you are not an internet behemoth like Google or Netflix, and even if you have relatively small applications with much fewer users, the costs accumulate over time. but without tls amazon can "decrypt" your traffic and see whats inside. There's a case for tiny images, but it's in severely-constrained environments. Perhaps in a desktop environment with hundreds or thousands of different programs running, it might make a difference. Do you really need grep, ls, or bash in your production container image? it should probably be called "package-manager-less" because there's no package manager in the final build, but there's also no ls, etc, so distroless kinda makes sense. > Id think that a few megabytes of disk isnt as valuable as the extra cpu cycles. Running snyk container test geo-alpine returns: The distroless Dockerfile acts a bit different than the two above. Why reduce the docker image containers size? - Here's How to Fix Common Issues, #16- The Batman Arkham Games in Chronological Order, #17- What is ERC-3475? Google, which seemed to start this movement, is publishing their own distroless images for Java, Python, Go and C++. That said even. Instead, distroless images are a class of minimal images which contain only your application and the applications runtime dependencies. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Azure Policy for Kubernetes: Contraints and ConstraintTemplates, CA certs: no need to copy them from stage 1, /etc/passwd: contains users and groups such as nonroot, tzdata: in case you want to set the timezone other than UTC, Here's my webinar on Flux v2 on AKS for ESPCs Azure Week. Look Docker, No Distro. It's much simpler and more oriented towards POSIX compatibility than performance. Why? You can look at strlen in the K&R book and it's beautiful, like a textbook: GLIBC is full of stuff like that. Which is quite a bit. Nah, not worth it. I heard about this "oh, it's shared, don't worry" thing before. Could you elaborate on what some the "wide variety of software" is? Please identify your camp and explain why. Find out what else Avenga is doing here and also check out our LinkedIn profile. int strlen(char s[]) Alpine meant for instance, that Python containers had to download all the dependencies and as a consequence they have become bigger with the Alpine base image than without it (sic!). [1]: For me it's mostly a non-issue. qsort and memcpy are non-obvious to many folks. Our experts working for the complex solutions in pharma, insurance, banking and industrial sectors share their views. Not to mention, you still need runtimes if you are programming in Java, Python or many other languages. Its the new 3x SQLServer + 2x IIS + 2x SharePoint cluster to serve an intranet for 100 staff when a single would be more than sufficient. I've only ever done it when I needed to run exactly two processes- porting an older piece of software that was not originally designed to run inside containers, and orchestrating the separate processes to be able to communicate. It all takes time, time spent on a disk I/O and a networking I/O. Tested 37 dependencies for known issues, no vulnerable paths found. A number of packages is a bit older versions, though. It's sad to me that it wasn't obvious to you 5*5 is not 40, or 40/5 is not 5. With the scratch base image, we manually have to add CA certificates. With samepage merging it's nothing, let alone docker only loading the image once. The article linked below provides a deep dive into multi-stage builds. (Confusing right?!). It's more complex, no question, but it's much faster. I don't remember the last project I did which didn't have some sort of integration with an external service. Note that you do not (usually) have the package manager in a distroless base image (which can be shocking at first). We will also build the Golang version of the application in a variety of other ways: You have probably seen a Dockerfile that goes something like.

Using Snyk, we can scan the Docker images for vulnerabilities.golang:1.16-debian has 164 known vulnerabilities, 14 of those being high severity. That is very likely due to processor/architecture optimized precompiled Python. Or it can in the FS cache, in which case bits will be evicted as necessary to make room for executables. Any distribution we find is bound to have packages which we do not need. Why and When Do You Have to Use it? Whereas in musl, since the binaries all have their own copies of procedures, they are more often kicked out of cache. Clear Linux is definitely an interesting project, however, using base image with 'latest' tag (only tag existing for, If you want small images, why not use a tool like. We copy and install only the production dependencies. Scratch contains nothing in it except for the executable binary which you add to it. A distroless image is a slimmed down Linux distribution image plus the application runtime, resulting in the minimum set of binary dependencies required for the application to run. Secondly, we are running the binary as root. You should only need to push the base image once. In a large org devops people will quickly explain the benefits of standardizing on one, at most two, base images. You're only playing that 40mb once though. In the Go(lang) environment distroless images have been around for quite a while. If you've somehow statically compiled all your dependencies, shouldn't that just run without a container? Alpine Linux Docker images have NULL for root pass, Usually, Linux distribution based docker images contain tons of stuff you wont ever need, but hackers can use it to hack into your system. Since Golang is a compiled language, we can use a scratch base image in a multi-stage build. Without a shell, how does one debug if anything goes wrong? The base image may be small, but all the packages and metadata are large, and the dependencies are many. "Xless" is just a different way of saying "without X". In production, the smallest box has half a gig of RAM. Expect when it isn't. The problem is that we are looking at the problem from the wrong angle. Let whatever is managing your container restart it if the process quits, be it docker or K8s. And there are min spec machines which are cheap in the cloud, so fitting more containers into one machine means less machine spawns. from the host system, containers don't exist in a vacuum. For many languages, JavaScript and Python included, which are interpreted instead of compiled, a scratch image wont work. Distroless images came out around 2017. I just think the name of the project is strongly misleading. Its good but it has some trade-offs. Change). For a large cluster it's a wash. You might as well use Ubuntu, Centos -- anything where there are people working fulltime to fix CVEs quickly. Let someone else worry about watching all the upstream dependencies, let someone else find and fix all the weird things that build systems can barf up, let someone else do all the heavy testing so you don't have to. I've no idea why you wouldn't use Ubuntu which is only around 40mb, has a sane package manager and a standard glibc. As it happens, you're describing one of the motivations for Cloud Native Buildpacks[0]: consistent image layering leading to (very) efficient image updates. And it still takes time to download. The argument above is that you shouldn't do this and should instead plumb that ingressing TLS traffic all the way to the container. We then copy over the build and the node-modules to a distroless image and run the application. How to set Java environment variable in Ubuntu, How To Make Amazing Screencasts Nobody Will Watch, What Are Ngx-Admin dashboards with Backend, and Why Do You Need Them. To know more about us, visit If you're a small company, you have much lower hanging fruit to chase. You simply cannot write to a disk without a Docker volume. This article describes one of the latest trends in the container world - its called distroless containers. Computers are faster and have more resources so maybe its not that important. I've heard that having shared libraries like glibc allows for commonly shared hotpaths to remain in the CPU cache, making it faster. Who, when, and how will it update your local distroless image? Next we copy the code. I wonder how reproducible it is, and what the reason might be. If your image size is 500 MB then you can fit two, but if you can reduce it to 100 MB then you can fit ten containers. What's an extremely easy solution to set up and maintain automated certificate signing and provisioning? It just runs Java apps on top of a slimmed down Debian instance. When it comes to Go and the scratch image, I prefer using distroless static. Again no apt or pip, you have to install the dependencies in another way. I don't want to disparage any project or guess the motivation but there have been some undercurrents of anti-GPL sentiment at times and anti-complexity. We use alpine as our first base image. ), to scan the containers for known vulnerabilities using scanners. This has nothing to do with being a LB, if you need to do outgoing calls with https you most likely need ca-certificates. Because it's tiny, I tend to default to Alpine and then move away from it where necessary. afak there is no easy and trivial way to "passively clone" aka dump memory of the hypervisor all the time without it being detectable in slowdowns and so on. (LogOut/ PyInstaller freezes (packages) Python applications into stand-alone executables. You've discovered the charming little fact that the registry API will report. Next we copy the code and run pyinstaller on But for sure, distroless images are a thing and you definitely should give it a try. Booo, theres no Linux shell here! Amazed more people don't know this. Many debian based images set this option by default. We, at Avenga, have used distroless containers in production environments for more than 3 months and are already using multi-stage builds. not necessarily. Its awesome that the images are pretty small, but a wide variety of software has been shown to run noticeably slower on Alpine compared to other distributions, in part due to its usage of musl instead of glibc. If it's relatively very different, absolutely speaking its 40mb which is very little even if you have to transfer it up.,, Anyway, project wide I can say that in most cases its option 1, in some option 2 and 3. This is the second article in the four part series, Minimizing & Securing Docker Images. 164 known vulnerabilities, 14 of those being high severity. This is the second article in a four part series. If your software is heavily CPU-bound, and the difference matters for you, you can likely find or build a highly optimized image for your particular number-crunching task. }. Recently folks have done this with One Multibuild To Rule Them All. Just run your entrypoint with an unprivileged user id and make the root folder unwriteable. The size of the above distroless image is around 30MB. In times where everyone pushes their branches early-and-often and CI/CD is in place, faster downloads and less space used in the Docker Registry is a plus on its own. Scratch is an empty image, so it is ideal for statically linked binaries that do not require libc. Certainly for embedded devices, probably also for clusters. I don't imagine it has a big impact on a container where you are only running one or two binaries.

However, this is just the start. Much like a classic car enthusiast, who knows exactly whats in his car, we will build our Docker images knowing exactly what goes into them. For almost any serious job running in production, you might need CA certificates and openssl. Good and simple explanations. The downside of plumbing directly to the container is that you lose many of the routing features of a service mesh.;a=blob;f=string/strl For statically linked binaries, why wouldn't you use the SCRATCH (0 kb) 'image'? It's not quite as easy to get started as with something like Ubuntu though. As you can see, all three share the image ID of b09f7387a719. the Parallel So when I talk about openssl in the image, I was referring to the `base` flavor. Binaries are binaries, whether you copied from a deb package or completely built from source code (assuming reproducible build, which Debian supports), they are the same. Youll be able to see some examples below of multi-stage builds, as we analyze the Dockerfiles of the different repos linked above. Is distroless the true and final savior? That said, the distroless trend is absolutely the right direction. On recent projects weve moved to using multistage builds and minified containers; mostly Alpine based but also distorless. By the time you're going to the trouble of reinventing buildpacks why not just use buildpacks? Distroless takes the upper-hand when it comes to having no package manager or shell. It's not just a few megabytes, it's more like hundreds. * musl prioritizes thread safety and static linking over performance Although, in my experience, you can go very far within your vpc. If your binary is static, why do you need a container at all? However multi-stage builds allow us to optimize and reduce the size of our images by selectively copying over artifacts from one base image to another. Distroless images are here. This has to be addressed, otherwise, without proper maintenance and base dependencies updates, it will rust very quickly and defeat the purpose of its creation. Tested 431 dependencies for known issues, found 349 issues. Remember your favorite cloud provider and its offer. The same goes for docker images, but the fight is for MBs rather than seconds. So we can have both, the temporary package manager in a temporary docker image and the flattened file system resulting in a smaller image. Add to that that modern Ubuntu uses systemd which greatly exhausts the systems inotify limits, so running 3-4 Ubuntu-containers can easily kill a systems ability to use inotify at all, across containers and the host system. There is not even a shell to docker exec into, however rule #1 of Docker security is, never run your application as root. Alpine always leans to conservative options and intentionally removes mostly-unnecessary things. I don't quite get it. This article describes one of the latest trends in the container world - its called distroless containers. I all comes down to what you need exactly or how explicit you want to be. Exactly. Images built from dockerfiles can do this too, but it requires some degree of centralisation and control. We copy the newly created dist folder to a new distroless image and run the app. It contains a minimal Linux, glibc-based system with: Once again, static images are the simplest distroless images. Felix Hassert, Avenga, Director of Products & Hosting. Your tech debt may grow slower that way. e.g. Lets compare some of the Dockerfiles we used to get the results seen above. Buster is the code name for the latest stable Debian version, 10.9. Why do they have to actively exploit hardware/vms that they own? For general cases, the former is preferable. This makes it especially easy to use distroless containers. The risk however is that automated dependency findings may fail and result in a runtime container unable to run your application. Unless you're behind a load balancer which terminates TLS and the traffic you deal with is purely http. >Today we are simplifying the process of building secure web applications by giving you the ability to make use of TLS (Transport Layer Security) connections that terminate at a Network Load Balancer (you can think of TLS as providing the S in HTTPS). However, even for the Go software it can be tricky to run in a scratch container. #10- The Best Online Platforms to Learn Something New, Today! stunnel/unbound DNS. Another approach is to use a standard base image (not minimized) and then use automatic tools to detect dependencies and remove files that are not needed. Next, node-prune comes in and helps us reduce our size even more. So in my opinon the name correctly suggests that it's "just the package" and comes "without a distro", and not "was built without the help of a distribution". So you can justify using k8s and shine up your resume! I do agree that people prematurely optimise and mainly incorrectly consider disk space but I think there's a decent use case for tiny images. Causing all kind of fun issues, I assure you. Depends. Fill in your details below or click an icon to log in: You are commenting using your account. There are no hidden dependencies. If our goal is to reduce the image size why are we trying to find smaller and smaller distros? or you can debug from the host system where the container's pid namespace is a descendant of the root namespace and the other namespaces can be accessed via /proc or unshare. I remember the days when deploying .war to a Java Web Application Server was a several minute task where now micro-frameworks fight for sub-second startup time. Pulling a Docker image by specifying a tag version golang:1.16 or by pulling the latest version golang will produce the same result as golang:1.16-buster. I would also add that data transfers cost money, and having to transfer a few hundred MBs each time a container image is passed around can reflect in the expenses. We copy the requirements.txt, and install them along with upgrading pip. ++i Because I like the pattern of building the binary in a container, I prefer a multi-stage build . Similar to the Node distroless image, the Python distroless image,, is built off of the base image but with Python 3 and its dependencies. Worst case for more disk use, things start crashing. Now that supposedly shared image is half a gig. #13- Apple CarPlay Not Working? #12- What is One Hot Encoding? So the cost is not just about disk-space. 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Why would anyone run an init system inside a container? It's faster in terms of development time. There is hope for shrinking images sizes for programs that are not written in compiled languages. I have always been a bit surprised at the popularity of Alpine Linux for docker images. Checked it out, is Intel supported with compiler tweaks to get the most out of their CPUs, for libs like math, pandas, etc. Unless you specifically need this image, in most cases it is not necessary. Normally I would do with golang apps. Do you get all developers to agree on which base image to build all their services from? Alpine with glibc? node-prune is a small tool to prune unnecessary files from ./node_modules, such as markdown, typescript source files, and so on. Don't feel bad. Without files, there is no hassle with file permissions. The `FROM SCRATCH` directive is not only distroless, its literally empty. Lets imagine you want to pay only for a low spec machine with just 1 GB of RAM. The CA certs are already in the image and /etc/passwd contains a nonroot user and group. Although these vulnerabilities are not ideal, using a distroless image over an Alpine image offers some advantages. Multiple containers sharing the same parent layers will not require additional storage for the core OS layer. As far as I'm aware you'd have to load that 80mb into memory for each docker container you run so that can add up if you want to run a bunch of containers on a cheap host with 1GB of RAM. See e.g. A step up from the static image, with more added packages, is the base image. "Don't worry, it's shared anyway". Computing Jacek Chmiel is an experienced system architect, tech leader, tech researcher. > all developers to agree on which base image to build all their services from. I think GP is probably thinking of kerberos/NSS, which has a plugin system that requires dynamic linking. For anyone who want a small image but with glibc. Already we can run and orchestrate 2.85 times more containers, using the same disk space. Disclosure: I worked on Cloud Native Buildpacks for a little while. given that containers usually do not include any init system at all thats not a good reason to pick a side. AWS is kind of a black box to me but it seems hopeless to try to protect data from people that physically control the systems. Rather than worrying about potential disk space issues upfront just use glibc and everything works fast and fine. Then we copy everything to a new buster base image and run the app. Multiplied by a thousand containers, and much larger layers on build servers, plus bandwidth, it makes a difference. It's not complexity for no reason, you'd be challenged to build a better qsort than the one in glibc, it's not easy. But theres statistics and practice. Thanks. Instead, we will focus on reducing base image sizes with distroless images, removing unneeded dependencies, and multi-stage builds. Bigger .dockerignore, Smaller Docker Images2. Alpine musl libc and busybox lack GNU glibc support and lack of GNU glibc support means trouble. A better signal to noise for container security scanners is one of the important reasons for distroless containers, also less files to scan and less I/O and CPU consumption for scanning as well. The base distroless image,, contains everything from the static image plus: Base images are best used for Go apps that required libc/cgo and all other statically-compiled applications that the static image cant serve. Or maybe you dont use libc at all in your fast path? Depends on your workload, of course. I don't think your LXC experience applies to Docker. I wonder if this would be important with service mesh and mutual tls Service meshes make in-cluster mTLS a more-or-less automatic feature, which is worth having.