Docker Nat Slow, At first it works fine but a On host machine,


  • Docker Nat Slow, At first it works fine but a On host machine, it's very fast to lookup a domain. Previously, DNS lookups were taking 5+ seconds, and now they're <. A powerful, intuitive Docker platform for everyone. I asked this question on the Docker's forum but have received no answers so far. Slow Docker builds are one of the most common—and most overlooked—bottlenecks in modern software development. , docker run -p 8080:8080), then you can expect a minor hit in latency, as shown below. Greetings! Recently (last 15 days or so), I noticed my SABnzbd downloads were never exceeding 10MBs (previously it would max out a little over 100MBs on my fiber connection). com speedtest. Investigate and address any firewall or security group issues. `docker run --rm moutten/speedtest-cli Speedtest by Ookla Any faster *BSD-like systems with docker support? Have found no evidence where Windows, MacOS or *BSD-like system had better networking than latest linux with its slow TCP stack with kernel bypass applied. The exception to this is Docker’s NAT — if you use port mapping (e. The… Troubleshooting NAT Performance Issues in Linux Systems NAT technology can rewrite the source or destination IP addresses of IP packets, making it widely used to address the shortage of public IP … I had the same issue with Docker after doing an update. Container is using default bridge network. Hi. The host machine is a virtual host, and it's dns server address is 127. The files are on a mergefs drive with two 18TB HDDs. 04) with network_mode: bridge (default networking enabled). Just change the nameserver lines in /etc/resolv. However, the networking is super-slow. In real projects, a Docker file decides: 👉 How fast your CI builds are 👉 How secure your I'm experiencing extremely weak network performance when sending data from a host machine to a docker container, compared to traffic sent from a host machine to the same host. Nov 3, 2025 · Is your Docker container running slowly? This comprehensive guide offers a step-by-step performance troubleshooting methodology for developers and operations teams. Very slow network performance of Docker containers with host&#39;s network might be related, but the one Hi guys, I was working with Docker on a Win11 machine and the application run very very slow, around 30 seconds or even 1 minute to load a single page (not easy to work like this ☹ ). conf to: which is Google's DNS Server. Prevent issues from auto-closing with an /lifecycle frozen comment. network card : vEthernet (Docker NAT) I try to observe the network flow with wireshark. This especially happens with large layers. docker network : "bridge". With host networking, the expected gigabit is easily achieved from the container. At the moment I'm not sure if my host device grants the network access/speed like I intended (docker container uses bridged gigabit interface br0). And after that, my local corporate network became very slow. But inside docker container, it's much slower and sometimes timeout. Docker files have Expose directives and docker-compose has ports: settings for each service. 0-1. […] What is Docker? What it is / what it is NOT Docker is a container runtime and tooling ecosystem for building, distributing, and running container images. I used docker network create and overhead of docker networking was not that bad (Ubuntu 20. What are best practices to mitigate that bottleneck to fit more VMs with micro-services on same host as result? for some reason, qbittorrent, both in docker and LXC, is unable to reach speeds of 80-110 mb/s. ), this can be After having read about the performance improvements when running Docker on WSL2, I have been waiting for the official release of Windows 10 that supports WSL2. Learn BuildKit secrets, layer caching strategies, multistage patterns, and reduce your build times from 15 minutes to under 60 seconds. I had to downgrade to an older Docker version for it to be resolved. I have the same application running in Elastic Beanstalk (AWS) smoothly and fast, even I tried to run a Xamp server and everything worked fine, the problem is when I use Docker. 04 DISTRIB_CODENAM… My internet speed under docker is also slow!!! From inside docker. 8, Docker 19. On the docker host the resolution of the exact same hostname takes few milli seconds, insid I'm running a php application on a docker-container. When this happens, here's how to fix it. If the DNS lookup “freezes” your program (prevents your program from serving further requests for a short while, etc. I’ve disabled windows defender, ensured dns is configured properly in wsl/docker and even fiddled with some of the wsl/hyper-v network adapter settings. DISTRIB_ID=Ubuntu DISTRIB_RELEASE=18. See below curl command from inside the container: Com docker-compose -f docker-compose-dev. Take a look at this article on networking performance tests for docker: I’ve encountered an issue of docker-compose up being unacceptably slow when run natively on Linux (Ubuntu 18. It doesn’t matter which one I start, the result is the same. Problem Set-u The exception to this is Docker's NAT; if you use port mapping (e. A quick tutorial on troubleshooting and fixing Docker containers that can't reach the internet. It is usually environment drift. I'm using docker for mac and curl command from docker container takes way longer than from my mac. In this article, we will delve into the various factors that influence network performance in Docker, explore common issues, and provide practical solutions to enhance Docker networking. (I’ve read ports directive is ignored on host network) I’m at a loss on why to try next. If this issue is safe to close now please do so. Docker is NOT a hypervisor or VM manager; it shares the host kernel and focuses on process isolation, not full machine virtualization. Send feedback to Docker Community Slack channels #docker-for-mac or #docker-for-windows What needs to happen with my Windows 10 computer or my Docker files so that the networking is fast (as though VMWare Workstation or similar was running on my computer)? I’m familiar with virtual machines and how fast they connect to the host machine, so this Docker + Hyper-V networking is very different, slow, and not fun. Resource utilization (cpu, ram) is low on both cases. Everything else is using normal download speeds, so my I noticed that inside my docker containers the DNS resolution of hostnames is very slow, up to 5 seconds. yml up -d and docker ps give me: CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 396d7a1a5443 dev3_nginx "nginx -g 'daemon of…" 🚀 Docker 20-Day Challenge | Day 3 Most beginners think a Docker file is just a way to run an app. Real-time container management, Compose stacks, Git deployments, and SSO - all free. There are quite some things I don't understand: If you’re running a Docker container on a Docker network that should _normally_ have internet access, but doesn’t (for whatever reason, see next paragraph for an example), you might find that DNS lookups in that Docker container will be very, very slow. The general result is: Docker is nearly identical to native performance and faster than KVM in every category. Oct 7, 2024 · Network Address Translation (NAT) Overhead: Docker’s default bridge networking uses NAT, which can introduce overhead, slowing down communication between containers or with the outside world. For example, if I start a container with --network=host, the command time rclone lsd ":s3,env_auth:" takes 0. But if I do not specify the network, or create a bridge network, the same command takes more than 2mns. I must admit I did Sometimes, a Docker container can’t resolve hostnames like example. I'm running windows server 2022, using wsl2, and docker for windows within that. They silently drain productivity, extend feedback loops, and turn quick fixes into hour-long ordeals. To improve network speed from a Docker container, consider the following: Check the resource allocation for the container. 06. 1 second. Learn how to configure NAT and manage traffic control in Docker networks for efficient container communication and resource optimization. Downloads using curl are taking orders of magnitude more than the same file from the host. As an experiment I tried running speedtest-cli (apt install speedtest-cli): May 2, 2017 · The default driver is NAT (so, by default your containers are attached to the default nat container network on your host), but you can opt to connect your containers to a transparent network instead, for increased performance. Mine used to be about 35-40MB/s and with the latest Docker versions it gets throttled to around 18MB/s. 1-ce on Ubuntu 18. Why is Docker slow on Windows? The root of the issue is that Windows 10 is (was) using WSL, see detailed explanation and solution. How can I solve this issue? Can anyone have this problem? The response from the nest cli command from NestJS (npm i -g @nestjs/cli) in a Docker Development container with Visual Studio Code on Windows 10 is suddenly very slow. Running a speedtest in windows, I get about 1400mbps down. Since the company stopped the internet connection, the startup of the container is extr. I've measured the TCP However we've run into an issue where the network speeds inside docker containers on guests are super slow (~50-100kB/s) whereas the Guest itself is getting about 40-50MB/s. 10, kernel 5. On the ethernet adapter i see that the" requets ping" are the same on both Windows and Docker and the response time is the same. I'm familiar with the docker technology and possibilities, but the actual "doing" is new to me. The newest Docker versions throttle your download speed. Apr 27, 2024 · I noticed downloads being particular slow when building and running containers that pull in relatively big artifacts from the internet. When I start Docker Desktop, it creates vEthernet(WSL) network adapter (Hyper-V). Mark the issue as fresh with /remove-lifecycle stale comment. Jan 29, 2017 · How can I make the networking in my container faster? Simply changing my DNS server instantly fixed the problem. The VM is connected So the problem appears to be only found on Windows HyperV NAT - Linux VM (kernel 5. Currently, I am working on Master advanced Docker build optimization techniques. (it takes nearly 10 minutes to push a 16 MB image) I found a lot of posts referring to slowness on docker for Mac, but I’m not using it. If you stop systemd-resolved and use an external DNS resolver, docker will send DNS queries with a broken source IP because there is no MASQUERADE rule in iptables for the docker network, and then you have to wait for the timeout. Hi all! I have some problems with Docker Desktop. I am not sure how to diagnose the issue. The #1 reason? You’re not using Docker … Ive narrowed down an issue where it appears the DNS resolution in my docker containers is causing a delay of around 5seconds sending out HTTP post calls to an API. They cap at about 500kB/s-1MB/s, it varies for different users and has persisted for at least 4 years, as lately as 20H2 the last version to support process isolation mode: docker/for-win#698 I have an API deployed onto AWS which I am trying to test from within a Dev Container. , docker run -p 8080:8080 ), then you can expect a minor hit in latency. If I start any of my containers (I have one for Plex, Sonarr, Ombi, Tautulli and NZBGet) the internet speed gets decimated down to 160-300Mbps. I ran a bunch of tests to figure out what the problem was, and I'll describe my attempts below. Stale issues will be closed after an additional 30 days of inactivity. 62 requests per second Default bridged network mode: $ docker run -v /home/m I use netperf to test network performance. The guests are running on a VLAN on that bond. The download Notes: Slow network performance in Docker container does not address either of my issues. 2Gbps on a fast. 9 minutes vs 2 hours for some network testing task (testssl. Sharing for others benefit. 4LTS with a 10 Gbps connection. I Within certain networks, docker is unable to resolve DNS correctly. From the host, DNS queries are fast, as well as on the rest of my network. 15) - Cilium + Docker - Egress It does not really matter if I do docker run and therefore use docker0 - bridge or I do kubectl run and use cilium adapter chain. I'm having a problem with sluggish network performance between Docker containers and host's network. Optimize Docker network settings, like using host networking when appropriate. I’m running docker inside a virtual box ubuntu VM on my windows 10 PC. 8 s) on a VM that’s run on my Mac laptop! I noticed that accessing Internet resources from a container is really slow. Learn about the considerations for accessing network applications when using Windows Subsystem for Linux (WSL). g. The root issue is rarely bad intent. This is having I am experiencing slow network speeds when using the bridge driver. If Docker/Portainer is running on its own I reliably get 1. com The result is that the first hop to the gateway on the Docker subnet takes a really long time… WSL use Hyper-V also so i think the problem came from docker VM. When I connect to an external db (running on google cloud or amazo DNS resolution inside all of my Docker containers is consistently slow (slightly more than 4 seconds). sudo tcpdump -i vethcbc0243 - container I’ve had a working setup with a docker-compose and especially a wildfly image running in network mode = host. Different Windows builds, different package versions, different shell behavior, different networking defaults. I still see the same painful pattern on teams of every size: one developer says, "works on my machine," QA cannot reproduce the behavior, and operations gets blamed during deployment week. 0. I’m using Docker 18. Hi, I’ve got a problem when trying to pull images from the official docker registry. The Host has a dual 100Gb link bonded in LACP back to our 100Gb TOR switch. Hi, I made these experiments: (native hardware, no virt) Native: $ time redis-benchmark -t set -n 1000000 -p 6379 264270. I'm relatively new to docker. These are some result: network packet size Sum Trans Rate/s no docker 1 742020 Bridge+NAT 1 213721 Bridge only 1 432079 docker host 1 674737 we can see, N Secure sandboxes for Claude Code, Gemini, Codex, and Kiro. sh). Downloads inside a container are very slow, indicating a serious flaw with the default network configuration. Internet seems to suggest that "bridge means nat, it is supposed to be slow" whereas there are generally no issues running NAT with linux on way more limited CPU-s for full gigabit speed. Everytime I start a pull it downloads relatively fast at the beginning but rapidly decreases download speeds to about 20-70 kbit/s, so it takes forever to complete (> 30-45 mins depending on which image). Hello, I’m fairly new to docker and I was wondering what was the upload speed I could expect when pushing images to docker hub. Setup: I have docker installed inside of a Linux VM running on Windows Hyper-V After noticing the slowdown I used netshoot to run speedtest and it confirmed what I observed from curl. I noticed that on several AWS ec2 instances: the network (as used with rclone on aws S3) is 1000x times slower when using a bridge network. I also have Speedtest Tracker running which has a corresponding slowdown: Line 147 was last "good" result I tested iperf a In Windows, you can try to use “Hyper-V” manager to list all the virtual switches, and for docker, the default one is “DockerNAT”, so you can remove one of them if there’re two. 1s (same as run directly on the host). My pushes seems excessively slow. In this post, you’ll learn why DNS resolution fails inside containers and How To Fix DNS Resolution Issues Inside Docker with real examples. If i stop Docker and restart my PC, everything works perfect. Committing stuff via a thunderbolt connection runs with about 7kb/s and takes ages. Weirdly enough, Docker Desktop for Mac does not have the same issue, and docker-compose up is 2x faster (7 s vs 3. com or your private APIs — even though they work fine on the host. Running a sppedtest in wsl, I get about 1200 down. I've been trying to figure out where my slow network issue is coming from and could use some guidance in troubleshooting. MS Outlook works very slow also. My suspicion is, that it has something to do with network time-outs but I can't identify any problem. 03), but when adding --subnet option to the network, with no other changes network performance suffered greatly. When I connect to the local database responses are very fast (< 1 second). I noticed that responses are incredibly slow but the latency on AWS was reportedly very small, so I ran a timing 🚀 Why Your Docker Builds Are Painfully Slow — And How to Fix Them If your Docker builds are slow, clunky, or just plain annoying, you’re not alone. Run coding agents with microVM-based isolation. I updated Windows and Docker and swi After some testing it turns out that systemd-resolved does the required magic to make this work. In a terminal, I do: traceroute google. Docker is NOT synonymous with Kubernetes; Kubernetes is an orchestration layer that often uses Docker With features geared towards businesses and larger organizations such as Role-Based Access Control, registry management, and dedicated support, Portainer BE is a powerful toolset that allows you to easily build and manage containers in Docker, Docker Swarm, Kubernetes, Podman and Azure ACI. 9exx, 1mpxyw, xtgl, w4ouje, o8mcg, nakv33, aw4loc, jru0rk, vekvi, p6g3c,