An introduction to configuring Domino for Docker
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The document discusses the implementation and management of Docker containers for IBM Domino applications, highlighting the advantages of using microservices architecture and virtualization. It emphasizes the importance of storage management, careful resource allocation, and the need for a solid understanding of Linux operating systems for effective container deployment. While Docker is beneficial for development and testing environments, the author advises against using it as a production architecture for Domino due to its dependence on disk performance and I/O.
An introduction to configuring Domino for Docker
- 1. Docker for Domino • Gabriella Davis • IBM Lifetime Champion for Social Business • [email protected]
- 2. Gab Davis • Admin of all things and especially quite complicated things where the fun is • Working with the design, deployment and security of IBM technologies within global infrastructures • working with the real world security and privacy aspects of expanding data ecosystems • Stubborn and relentless problem solver • http://turtleblog.infohttps:// www.turtlepartnership.com • IBM Lifetime Champion
- 3. Terminology In The World Of Containerisation
- 4. DevOps • DevOps or Developer Operations refers to the collaboration of software development and developers with IT operations • it refers to practices, processes and communication not specific technologies • good DevOps practices are designed around rapid, consistent and reliable systems • The goal of DevOps is to ensure the seamless delivery and maintenance of applications
- 5. Microservices • Applications were traditionally developed in entirety with every function of the application grouped together and operating in concert • for that reason applications can often be large, over developed and hard to update • a change to a single function has to be incorporated into the entire application without any impact • Microservices architecture refers to applications that are developed as separate functional or core services each operating in their own isolated container but able to talk to each other • updates are simpler and minimising the overall application size is easier by deploying just those micro services that are needed • Domino Tasks = Microservices ?
- 6. Virtualisation • Isolating applications running on a single physical server • Virtualisation allows us to use software to mimic physical hardware • Using virtual machines we can more easily create new server instances and scale them • This saves both time and cost • The use of virtual machines and virtual environments has grown exponentially in the past decade
- 7. Virtual Machine vs Container With little OS of their own, containers are more lightweight and allow the host OS and hardware to be utilised more efficiently Virtual Machines
- 8. Virtual Machine vs Container With little OS of their own, containers are more lightweight and allow the host OS and hardware to be utilised more efficiently Virtual Machines Containers
- 9. Virtual Machine or Container? It’s not an either / or - both architectures have their benefits and drawbacks Virtual Machine Container More isolated and more secure Portable, simple to move between hosts or deploy from development directly to production Can run different operating systems in each virtual machine and not be tied to the host OS Fast to start up with no OS overhead Able to granularly scale use of resources Able to make more efficient use of host resources More work to set up and manage Collectively dependent upon and all using the same host OS Each VM must have enough resources assigned to also run the VMs OS Potential for security vulnerability via a “bleed” from the container to the OS and the process that started it
- 10. Containers Offer.. • Self-contained sandbox environments that host applications including micro services • Containers do not have an entire OS installed inside them the way virtual servers do but instead share the OS of the host machine • Multiple containers can share the OS of a host machine with their own isolated application and file system • Container architecture is designed to be portable and simple to update / maintain • A container would usually contain a single service so that maximum benefit can be leveraged from the portability • one service or application to one container • each application environment is not dependent on the other
- 11. Docker • Docker is an open source container based virtualisation solution • There is both a “Docker” client and a “Docker” server • Docker is not the only container environment, there are others such as rkt (Rocket) but IBM are using Docker for Connections Pink and it’s supported in a wide variety of hosting environments including AWS, Azure and Rackspace • Docker can be quickly installed on Linux, Windows and Mac
- 12. Kubernetes and Docker Swarm • Containers must be deployed and managed • management tools aren’t easy • Containers can also be clustered and load managed by a cluster manager • Docker Swarm is a native cluster manager using the Docker API so it requires Docker containers • Kubernetes evolved out of Google’s expertise and was far ahead of Docker Swarm for many years but no longer • There are many tools out there to help cluster and manage Docker containers • If you are going to have exclusively docker containers than Docker Swarm may be a better approach than Kubernetes • Clustering at Container level has to be very carefully considered with Domino containers
- 13. Getting Started
- 14. Devops and Containers • Developers love containers • They make it easy to isolate microservices and swap out updated code • However that ease comes with risk • each container is drawing resources from the same host • each container has separately mounted storage and often nested dependencies • spawning a new container from an image will not deploy changes made inside an existing spawned container • Process is everything • Process is Operations and Development working together
- 15. Mac docker install supports Linux containers Windows docker install supports Windows 2016 server core containers and Linux (kind of)| using Linuxkit (don’t do it!)
- 16. Images and Containers • You don’t run the image itself but use the Docker server to spawn a container based upon that image • You can spawn as many containers as you want using the same image on the same host • Each time a new container starts it is given a name, an ID and a tag • Changes made inside the container are not saved when you quit it unless you commit those changes back to a new image • Starting a container from an image also includes mounting storage • So is having a re-usable Domino image useful? IMAGE CONTAINER ID TAG Running Process NEW IMAGE docker run spawns a container instance based on an image docker commit creates a new image based on a container Name
- 17. Commands For Reviewing Containers • Once docker CE or EE is installed and active the command “docker” will work in a command window • docker images - shows all existing images in the registry • docker ps - shows all existing containers
- 18. Docker Pull Images • the Docker Store (store.docker.com) has hundreds of containers that you can use • docker pull microsoft/windowsservercore (the windows 2016 server core container) • docker pull registry.access.redhat.com/rhel7 (rhel 7) • docker pull mongo • docker pull store/ibmcorp/db2_developer_c:11.1.3.3-x86_64 • For Domino I use RHEL • There are many CentOS and Debian containers available but those are not supported Domino platforms
- 19. Images & Containers • docker image ls - to show all available images • docker ps —all to show all running and non running containers • docker-machine <command> <machinename> e.g. docker-machine inspect turtle test • docker exec <container name>- run a new process in the named container e.g. bash
- 20. Commands For Containers • docker run - lets you start a new container from an image • -d starts in background mode -i starts in interactive mode • https://docs.docker.com/engine/reference/commandline/run/ • docker attach - lets you connect to a running container • CTRL P, CTRL Q exists a running container without closing it • CTRL D - exits and closes a container, this isn’t the same as removing it but does lose all your changes • docker logs <containername>
- 22. Using Docker For Domino? • Using the image registry.access.redhat.com/rhel7 docker run -t —i -v /Users/GabAir/Downloads/Notesdata:/home -p 1352:1352 -p 80:80 registry.access.redhat.com/rhel7 docker exec -i -t <containername> /bin/bash • docker commit <containername> <newimagename> • Development • Testing • Low priority cluster mate • DR hot swap • Consider disk and storage
- 24. Choosing an OS For Your Container • Domino runs on both Linux and Windows so how do we choose? • the OS kernel is on the host machine so that OS has to be a supported Domino OS • both the image and therefore the container access the host kernel for their core functionality • Windows 2016 and Windows 10 can run Docker CE and EE • Linuxkit can be used to run Linux containers on Windows (dodgy at best) • Windows containers are Windows 2016 core server • Domino on Docker will primarily run on a Linux host with a Linux container • Adding an extra layer of running a Linux container on a Windows docker install impacts performance
- 25. Resources • When creating a docker container from an image you do have some control over the resources on the host that it can consume. This includes • Maximum allowed memory • Allocated CPU % as a total of the host and/or relative to other containers running • This will prevent a container from consuming too much resource • However Domino cares about • disk performance • cpu • memory • designing the correct storage is the most critical aspect of a production container
- 26. Container Clustering With Domino • Clustering at Container level has to be very carefully designed if you’re deploying Domino containers • Domino won’t like container clustering across identical live Domino servers • Data storage should be outside the container as containers are designed to be temporary and self destruct on quitting (more on that in a bit) • Having a failover cluster as a Domino container • Having multiple active / passive containers representing the same Domino server File based storage for MailA Domino Active Container MailA Domino Passive Container MailA
- 27. Docker Storage
- 28. Docker Data Volumes • Shared storage areas that can be used by the containers to access data on the host or within another container • You don’t create volumes within a container so you create volumes that link to either data stored in another container or on the host • Volumes defined in an image and deployed as the container creates can only be applied to that container and are not removed when it is removed • Volumes defined within a container can be accessed by other containers using the volumes- from option
- 29. Data Volume Containers • You are essentially creating containers to be NFS stores • Since they are containers they can be moved to new locations and the references to them will still work • However if the data container isn’t running the data can’t be reached • Backing up the data means backing up the container • All containers that mount that volume are reading and writing to the same space • Be careful not to destroy the data Container • Docker has limited data integrity protection
- 30. Directory Mounts • A location on the host machine that is “mapped” to a mount point essentially in one or multiple containers • It is accessible and exists regardless of whether any containers are running or using it • It can be backed up as standard data storage • Access is controlled by host file permissions • It can’t be as easily moved to a new location • Be careful of tying yourself in knots with relative references to data volumes • Be VERY careful of launching a container if you don’t know the mount points that are defined inside it
- 31. Directory Mounts vs Docker Data Volumes • A directory mount can be assigned to multiple containers even after they are created • A directory mount can point to any part of the host file system that the account running the docker container has access to • Directory Mounts have security and data loss risks that need to be carefully managed • Data volumes are created when the container is created and cannot be re- used directly by other containers • Docker data volumes are created within the docker file structure on the host and are managed (or not managed) separately from the container • Deleting a container will not remove the data volume
- 32. Risks • Storage containers can easily be deleted • especially if it’s not clear that another container is using that storage • Directory mounts can be easily overwritten if another container runs with the same mount points • Deploying new code via a container that retains the storage references from a previous version will overwrite production storage • Ease of use and flexibility must be tempered with Devops process and planning
- 34. Docker Networking • Docker can create a private network for each container it starts • Containers can be linked together to share the same private network and isolate themselves from other containers started by the same docker machine • by linking containers you can ensure if they are killed then recreated with the same name, the network link is maintained • We can also tell the docker server to expose specific ports inside the containers to external ports that can be reached outside the containers. For instance a port 25 SMTP listener or 443 web server (old school method)
- 35. Bridged Driver Networks • Each container is created as part of a defined bridged network • The bridge networks are private and on their own subnet • Containers on the same bridge network can be seen and addressed within their own private network without routing traffic through the host
- 36. Overlay Driver Networks • Each container is created as part of a defined overlay network • Overlays are similar to bridge networks but are designed to work with multi host networks so containers do not have to be on the same host to see each other • Docker swarm is used to manage and route traffic between containers using the overlay driver
- 37. Port Forwarding • When running the containers we specify both a port to open and how it is reached from the host machine • This port forwarding can then be used by other containers to talk to each other via the host
- 38. Macvlan Drivers • Each container is created as part of the host network • The routing and accessibility is controlled as if the container were simply another machine on the host network • This makes macvlan the most lightweight of drivers
- 39. Summary • Docker is a great architecture for temporary or changing environments such as development • It really does require understanding and a level of comfort with Linux OS • Containers are designed to destroy themselves and their content unless you specify otherwise so in most cases we want to keep content outside the container • Domino runs well on Docker for Linux but it really isn’t a collection of microservices (yet**) so isn’t taking advantage of the core architectural benefits of containers • ** hello HCL - one for the wishlist • Domino is very dependent on disk performance and I/O so choosing and optimising the right storage is critical • Deploying docker as production architecture for Domino is not something I’d recommend but for test, development or small scale failover it is a good solution