Both type LoadBalancer and NodePort work on Docker for Mac Kubernetes. It's a lovely bit of magic, actually. Just hit localhost:[port]. For NodePort, a port is automatically assigned unless specified in the service definition. For type LoadBalancer, it is also specified in the service definition. Docker for Mac now ships with Kubernetes built-in! Let's explore why this matters, a history of developer tooling & my first impressions as I kick the tyres. Containers (which normally means Linux containers) were not available on Windows or Mac when Docker began its story as a spin-out from.
Jan 29, 2018 by During, Docker announced support and integration for Kubernetes, alongside Swarm. The first integration is in the Docker for Mac, where you can run now a 1 node Kubernetes cluster. This allows you to deploy apps with Docker-compose files to that local Kubernetes cluster via the docker cli. In this blogpost, I’ll cover what you need to know about this integration and how to make the most out of it. Why we need local orchestration While a lot of computing workload moves to the cloud, the local environment is still relevant. This is the first place where software is built, executed and where (unit) tests run. Docker, helped us to get rid of the famous “it works on my machine” by automating the repetitive and error-prone tasks.
But unless you’re into building “hello world” apps, you’ll have to manage the lifecycle of a bunch of containers that need to work together. Thus, you’ll need management for your running containers, commonly called nowadays orchestration. All major software orchestration platforms have their own “mini” distribution that can run on a developer machine. If you work with Mesos you have (container based), for Kubernetes there is (virtual machine). RedHat offers both a virtual machine and a container based tool ( cli) for their K8s distribution (Openshift). Docker has, orchestration and since recently also supports (for now only in Docker for Mac).
If you’re new to Kubernetes you’ll wanna familiarize with the basic concepts using this we build together with Google,. Installation Enabling Kubernetes in Docker for Mac, will install a containerized distribution of Kubernetes and it’s cli , which will allow you to interact with the cluster. On resource level, the new cluster will use whatever Docker for Mac has available for use. The release is in beta (at the time of writing the article) and available via the Docker Edge channel. Once you’re logged in with your Docker account, you can enable Kubernetes via the dedicated menu from the UI: At this point, if you never connected to a Kubernetes cluster on your Mac, you’re good to go.
Kubectl will point to the new (and only) configured cluster. If this is not the case, you’ll need to point kubectl to the right cluster. Docker for Mac will not change your default Kubernetes context. You’ll need to manually switch the context to ‘docker-for-desktop’.
KubeDNS is running at https: //localhost:6443/api/v1/namespaces/kube-system/services/kube-dns/proxy Note: You may have already another kubectl installed on your machine (E.g. Installed via gcloud utility if you used GKE before, or as a stand-alone program if you used minikube). Docker will install automatically a new kubectl binary in /usr/local/bin/. You’ll need to decide which one you’ll keep.
Deploying apps on the local Kubernetes cluster via Docker for Mac Ok, let’s try to install our first apps using a Docker-compose file. Yes, the previous sentence is correct. If you want to deploy apps to your new local Kubernetes cluster using the docker cli, docker-compose file is the only way. If you already have some Kubernetes manifests you plan to deploy, you can do it using the known way, with kubectl. We’re using here the demo-app from the official docker-page about Kubernetes.
Kubectl get all NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE deploy/db 1 1 1 1 39s deploy/web 1 1 1 1 39s deploy/words 1 1 1 1 39s NAME DESIRED CURRENT READY AGE rs/db-794c8bc8d9 1 1 1 39s rs/web-54cbf7d7fb 1 1 1 39s rs/words-575cd67dff 1 1 1 39s NAME READY STATUS RESTARTS AGE po/db-794c8bc8d9-mrw79 1/1 Running 0 39s po/web-54cbf7d7fb-mx4c7 1/1 Running 0 39s po/words-575cd67dff-ddgw2 1/1 Running 0 39s NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE svc/db ClusterIP None 55555/TCP 39s svc/web LoadBalancer 10.96.17.0/TCP 39s svc/words ClusterIP None 55555/TCP 39s. Svc / words ClusterIP None 55555 / TCP 39s Doing any change in the docker-compose file and re-deploying it (e.g.
Change the number of replicas, change the image version) will update the Kubernetes app accordingly. The concept of namespaces is supported as well via the -namespace parameter. Deleting the application stacks can also be done via the docker cli. Implementation details Will Docker for Mac allow you to deploy with the docker cli the compose-files on other Kubernetes cluster? No, it won’t.
Trying to deploy the same file on another cluster will return this error. '/apis/compose.docker.com/v1beta1' So at this point, if you want to deploy the same application stack on other clusters, you need to use something like Kompose to convert docker-compose files to Kubernetes manifests (it didn’t work for my example), or write the manifests by hand.
Are you a Linux user who switched to Mac when you saw that Docker is now available as a native Mac app? Have you heard how great Docker is and want to give it a? Did you think that you could just take your Docker Compose file, launch your project, and have everything work out for you? Well you were right. Docker for Mac is a pretty smart invention. It gives you the whole Docker API available from the terminal, even though Docker itself wasn’t created to work on Macs.
To make all this possible, a light Alpine Linux image is fired up underneath with xhyve MacOS native virtualization. Because of this, you need to allocate CPU cores and RAM for the VM.
Things won’t be as close to bare metal as they are in Linux. If you are – for example – a Java developer who uses Docker to run compiled JAR, you may even not notice the difference. At least, as long as you don’t try to do any heavy database work.
Docker for Mac and Full Sync on Flush Issue First, let’s look at MacOS: “For applications that require tighter guarantees about the integrity of their data, Mac OS X provides the FFULLFSYNC fcntl. The FFULLFSYNC fcntl asks the drive to flush all buffered data to permanent storage. Applications, such as databases, that require a strict ordering of writes should use FFULLFSYNC to ensure that their data is written in the order they expect.” In short, to keep our data safe, every change made in the database needs to be stored on disk in an exact order.
This will guarantee that during power loss or any unexpected event your data will be safe. Actually, this makes sense — if you decide to setup a database inside Docker for Mac on a production environment In most cases, though, you’ll be using your machine for dev purposes where you don’t care to recreate the database from fixtures. If you have a Macbook, even power loss isn’t a threat. In this case, you may decide to disable this.
While reading about Docker issues on GitHub, I found a solution provided. Things will get a lot faster when you type those few lines into your terminal: $ cd /Library/Containers/com.docker.docker/Data/database/ $ git reset -hard HEAD is now at cafabd0 Docker started $ cat com.docker.driver.amd64-linux/disk/full-sync-on-flush true $ echo false com.docker.driver.amd64-linux/disk/full-sync-on-flush $ git add com.docker.driver.amd64-linux/disk/full-sync-on-flush $ git commit -s -m 'Disable flushing' master dc32fcc Disable flushing 1 file changed, 1 insertion(+), 1 deletion(-) Actually, someone even placed to make things easier. Does It Really Work? I created a to check this.
This test uses a standard Docker MySQL image without tweaks, and an image with sysbench installed. In my test case, I decided to use one thread (I only allocated one core for Docker on my Macbook) and a table with 10,000 rows.
I ran it twice: once with flushing enabled (default), and once with flushing disabled. If you’re skeptical about performance gain after changing just one value from true to false, then let the results below change your mind.