Here is a small checklist about how to migrate a legacy migration and to ensure its success.
This article is part of my work to explain my knowledge about Software migration in the company Byoskill.
To be or not to be (happy), that’s the question. In this article, I expose some thoughts about what could make a software developer happy in his work. I wrote this article with several targeted audience in mind : Junior developers, Senior Techleads and H&R resources.
This article is part of my working notes on the subject of “How to migrate Web applications running on JBoss AS 5 to the version 7”.
I will go straight to the details though here is some lines about JBoss Server.
From Wikipedia : JBoss Application Server(Now called Wildfly) is an application server authored by JBoss, now developed by Red Hat. WildFly is written in Java, and implements the Java Platform, Enterprise Edition (Java EE) specification. It runs on multiple platforms.
On 20 November 2014, JBoss Application Server was renamed Wildfly.
The product history according Wikipedia is :
The JBoss AS community project has been renamed to the WildFly community project wildfly.org
According this JBoss 5 to 7 in 11 steps, the benefits are :
Processing time decreased by 25% without any code change. Development speed increased in my opinion (it is really hard to measure it) by 50% and we are much more productive (faster server restarts). Memory footprint lowered from 1GB to 512MB. Finally automatic application redeployment finally works! However there is always a price to pay – the migration took us 4 weeks (2 sprints).
Thanks to the presentation from Roberto Cortez, we have a clear picture of the migration.
[slideshare id=54488564&doc=migrationtalesfromjavaee5to7-151028171122-lva1-app6892]
JBOSS 5 Architecture
JBOSS 7 Architecture
When the PAAS or the Web application server have to be upgraded, several regressions may happen. The team has to pay attention to :
Server functionalities and integration : between the versions, some functionalities and integrations provided by the server may have evolved, be fixed or simply disappeared.
Server configuration : The way the server has been configured, using scripts, GUI, may have changed, forcing the team to change their configuration files and finding the corresponding new way of doing it.
Server deployment configuration : Your deployment model configuration may have to be upgraded : single node, clustered mode, disaster recovery, high availability, reverse-proxying may behave differently in the new versions.
Application deployment configuration : the way to deploy your web applications may have changed in the new versions (GUI mode to script mode…)
Server API Regressions : usually Web Application servers are implementing a specific JEE API version, Servlet API and so on. These API may have changed causing regressions in your applications.
Application regressions : JBoss is including many components extending the JEE with BPM, Persistence, implementation. It is really important to track your dependencies (using Tattletale or mvn dependencies:tree) and interview your team about possible hacks and fixes to overcome the limits of JEE 5. This kind of workaround is difficult to migrate.
Training and risk management : This kind of migration contains its part of risks and changes. Both can create frictions inside your team of between the IT Team and your Dev teams. To ease the migration, don’t forget to dedicate some time to your teams into training to learn the new features of JAS 7. You will also have to adapt your project management to freeze for a while the features until the migration has been done.
This section is providing a checklist to help developers and managers to evaluate the migration risk of their applications.
Here is a list of common issues during the migration of applications with JBOSS AS.
4.2. Debug Migration Issues 4.2.1. Debug and Resolve Migration Issues 4.2.2. Debug and Resolve ClassNotFoundExceptions and NoClassDefFoundErrors 4.2.3. Find the JBoss Module Dependency 4.2.4. Find the JAR in the Previous Install 4.2.5. Debug and Resolve ClassCastExceptions 4.2.6. Debug and Resolve DuplicateServiceExceptions 4.2.7. Debug and Resolve JBoss Seam Debug Page Errors
Here is a summary of the evolutions between the JBoss AS version 5 and the version 6.
Here is the compiled list of modifications including the minor version fixes.
In JBoss Enterprise Application Platform 5, the class loading architecture was hierarchical. In JBoss Enterprise Application Platform 6, class loading is based on JBoss Modules. This offers true application isolation, hides server implementation classes, and only loads the classes your application needs. Class loading is concurrent for better performance. Applications written for JBoss Enterprise Application Platform 5 must be modified to specify module dependencies and in some cases, repackage archives.
Here is the compiled list of modifications including the minor version fixes.
Unlike previous releases, with AS 7.1, remote access requires secure authentication by default. This includes both managment (native, jmx, etc) and various remote application protocols (ejb, jndi, jms, etc); Added SSL support for the Remoting interfaces.
data-source add" "--pool-name" argument seems to have changed to “–name”.According link, we thought it would be really hard to connect with JMS server based on JBoss 5. It turned out that you have 2 options and both work fine:
In WildFly 8, a resource adapter is configured in the server configuration file. If you are running in domain mode, the configuration file is the domain/configuration/domain.xml file. If you are running in standalone mode, you will configure the resource adapter in the standalone/configuration/standalone.xml file.
More details there How to migrate from AS5 or AS6 to Wildfly
Here is the list of tasks implying some rewriting inside your application code.
Here is a list of useful tools to assist you in your migration.
In this short story, I will relate how I migrate my blog personal website from a classic VM instance to Google cloud using Kubernetes, Docker, Nginx.
Onoe of my personal goal was also to have a cloud deployed website without spending any money.
Long story made short, I have been using Docker on several projects since one year. I progressively got accustomed with the ease of deployment provided by Docker. The issue ? The day I have launched my blog (on February 2017),for time and cost reasons, I picked an VPS instance from OVH.
Why OVH ? Clearly it is one of the cheapest IAAS provider and quite popular there in France. I have been using it for several projects without any major issues.
OVH has an offer of public cloud OVH Public cloud. However the offer looked immature at that time both in documentation than on reviews. The second reason of my rejection is about cloud adotpion. A lot of experts are turned toward GCloud and AWS. Spending my efforts on OVH would not provide enough visibility at short term, in my job.
To better accompany my colleagues and customers to adopt the cloud , I have decided to eat my own dog food. And among my personal projects, I have decided to migrate first my blog.
And to switch my blog from OVH to Google Cloud (Container Engine).
Here are some interesting articles about pricing and functionalities for the major cloud providers :
My blog is hosted on a VPS server (shared instance on OVH). I have installed on it, Apache 2, some monitoring and security system and Let’s encrypt to obtain a free SSL certificate.
Hexo command line
My blog is not using the classifical wordpress, I am quite fond of static website generators and more recently of flat/headless CMS.
I am using HexoJS as a CMS. Main features are you are writing your article in Markdown and the blog has to be regenerated to produce the static files, producing quite optimized pages.
Hexo command line
These are the explanations how I proceed to migrate this website.
Yes, we have to start from the beginning and I created a new Google Cloud Account. Though it is rather easy to create its account, I have been surprised. It was impossible to for me to pick an individual account.
It’s even in the Google FAQ (FAQ).
{% blockquote By Google FAQ %} I’m located in Europe and would like to try out Google Cloud Platform. Why can’t I select an Individual account when registering? {% endblockquote %}
The reason (thanks EU.. ) is dumb as fuck : In the European Union, Google Cloud Platform services can be used for business purposes only
For information, in Switzerland, the limit is lifted.
Interesting enough, the free trial on Google Cloud has been expanded to 300$ for one year.
Well the UI is easy to manipulate even with this nagging collapsing menu on the right side.
Google Cloud Console
The documentation is quite abundant but I found two major issues :
I created a cluster with two VM instances, 0.6GB of RAM and 1 core. Indeed I wanted to play with the load balancing features of Kubernetes.
Create a cluster
The easiest and funniest part has been to reproduce my server configuration with Docker and to include an evolution. I wanted to switch from Apache 2 to Nginx.
First solution I created. I used a ready-made (and optimized) container image for Nginx and modified my build script to generate the Docker image. The generated website is already integrated into the Docker image.
FROM bringnow/nginx-letsencrypt:latest
RUN mkdir -p /data/nginx/cache
COPY docker/nginx/nginx.conf /etc/nginx/nginx.conf
COPY docker/letsencrypt /etc/letsencrypt
COPY docker/nginx/dhparam /etc/nginx/dhparam
COPY public /etc/nginx/htmlI made several tests using the command docker run to check the configuration on my own machine.
docker run --rm -i -t us.gcr.io/sylvainleroy-blog/blog:latest -name nginxMy second question has been how to store my Docker container ?
Creating my own registry ? Using a Cloud Registry ?
I have used two different container registries in my tests.
First is the Docker Hub.
Docker Hub
What I appreciate the most with the Docker Hub, is that I can delegate the creation of my Docker images to the Hub by triggering a build from GitHub. The mechanism is quite simple to enable and really convenient. Each modification of my DockerFile is triggering a build to create automatically my Docker image!
Here is a small draw to explain it :
Docker Hub & Builds draw
And some part of the configuration.
However Google Cloud is also offering a container engine and its usage has been redundant. I kept it to use it with CircleCI.
Therefore for the time being, I am storing my Docker container on Google Cloud.
Google Cloud Container Registry
With this kind of command :
gcloud docker -- push us.gcr.io/sylvainleroy-blog/blog:0.1
Maybe it is one my fancy side, but I have only used the GCloud CLI to perform the operations.
Everything go smoothly but don’t forget to install Kubernetes CLI.
gcloud components install kubectl
I had a problem with the CLI. It could not see my new projects (only some part of them) and I had to auth again.
gcloud auth login
And perform a new login to see the update.
Don’t forget to also add your cluster credentials using the GUI instructions (button connect near each cluster).
Google Cluster
gcloud container clusters get-credentials --zone us-central1-a blog
It took me time to understand what is a deployment and a pod. Using docker and docker-compose I could not attach the concepts.
That is one of my concerns with Kubernetes, some technical terms are poor and does not really help to understand what is behind.
Well, I finally create a deployment, to create two docker instances inside my pod (replica=2). This deployment file is declaring basically that it requires my previous Docker imamge and that I want two copies. The selector and the label mechanism is quite handy.
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: blog-deployment
spec:
replicas: 3
template:
metadata:
labels:
app: nginx
role: master
tier: frontend
spec:
containers:
- name: nginx
image: us.gcr.io/blog/blog:0.9
ports:
- containerPort: 80
name: http
- containerPort: 443
name: https I use such commands to create it :
̀kubectl create -f pod-blog.yml
KubeCtl Pod informations
I have automated the full cycle of my site generation, docker building and container registry and pod reload using CircleCI.
CircleCI Deployment Schema
And the good thing is that all these things are free.
After playing during two weeks with it on my spare time, I have the following feedback :
The deployment mechanism and how the rolling update is performed are impressive and a time-saver.. Some banks are still using an manual way or semi-automated way like Ansible to deploy their software and the rolling updates are performed awkwardly. Here Kubernetes is deploying on the background the new version, controlling its state (roughly) and if the conditions are met, switching from the old version to the new version. I am using this mechanism to bench my Docker new images and push the new versions.
I had to struggle a lot to set up my load balancer. Well, not at begin. Kubernetes and GCloud are describing precisely how to set-up a Level-4 LoadBalancer. It takes few lines of YAML and it was fine. However, I had huge difficulties when I decided to switch to TLS and my HTTPS Connection with Let’s encrypt.
I met several difficulties :
NodePork
To address the following issues, I found the temporary solutions :
The documentation about persistent volumes is not precise in Kubernetes and GCLoud and have important differences between the implementation and Google and even between versions.
You have many possibilities :
Another issue I have met, my docker container was failing (and the pod itself) because the persistent volume created is never formated.
But why ????
Indeed in your deployment file, you have properties to set the required partition format. But no formating will be performed.
And therefore I had the following next issues :
The recommended solution is to create an VM instance by HAND using Google Compute Engine, to mount attach the disk to the instance. To mount it manually and trigger the formatting. WTF
If you have a better way to handle the issue, I am really interested!
After a month of deployment, I haven’t spend a buck. My page response time decreased from 3.4s to 2.56s And I am not waking up during the night, the eyes full of horror thinking about how to reinstall the site. I only have a container to push.
I am not using yet the Kubernetes UI and I don’t see yet the necessity. The CLI offers almost everything.
Cleaning a cluster, the pods and deployments requires several steps and maybe could be simplified.
One very important aspect of my project was also to decrease the bill to host the site.
Currently, here is my bill for 1600 visits per month :
Compared to my 79€/year for my VPS.
Thanks to its popularity, Docker has disrupted many companies and blurred the silos between Developers and Operations. In this article, based partially on my own experiences, I will depict some of the disruptions that containers have provoked into the IT companies. I wish that this article will depict familiar situations and brings you argument to win the obstacles to the container technology propagation 🙂
Disclaimer : Despite I am quoting Docker quite a lot in this article, it is not an endorsed article. If you have a better alternative, simply replace Docker by another Container Technology, the arguments should still be valid.
If you appreciate this article, please relay or like it.
That is my first day on the job. A brand-new laptop, decent performance and feature. Default Operating system : Windows.
Well, I am a Linux hardcore developer and I spent many efforts to live without Excel, PowerPoint and Outlook. And who knows ? Maybe my customers won’t be on Windows. Therefore, I am wondering how to create my new software development environments ? Node.JS ? Java ? Mobile, each technology is coming with their own tools, servers and configuration.
What are the choices ? The company is fair and provides a decent laptop with sufficient power. However the software installation on the native OS has been blocked. I need to proceed by virtual machines. Virtual machines ? What a cumbersome solution. I need to download ISO or OVA’s and proceed to the installation of my software. What is your virtual machine creation’s strategy ? I made a quick survey to my colleagues, who confirm that they create a virtual machine by customer’s project. And they share their virtual machine like Pokemon. WTF ? Many dozen of gigabytes are transferred through USB3, a tiny hard drive and the team is ready. Well after several hours.
Docker or any similar container technology is offering me a better solution.
These are the following arguments :
Reduce your startup time and be more efficient. You can find many docker images to set up a development environment ready to use :
Broadcast your software programming best practices by using the same env in your team. As a tech lead, my mission is to make my colleagues better than me. And to reach that goal, I am trying to provide them the best tools, configuration, IDE, and automation to help them in their work. How many times, I had to provide a format style guideline to indent their code ? A syntax checker configuration ? An IDE with the right plugins ? All these issues can be solved by providing my docker image and updating it regularly.
The time for for Web IDE software is probably come : Eclipse and Visual Studio, Borland Delphi, such IDE have been used by generations of developers. They all come with the same advantages and drawbacks. Powerful, clever code completion, nice OS integration and notifications, a whole bad of features. Clearly the develop has a great environment to write its software but these solutions do not scale well inside a team. How to share my configuration ? My preferences ? How to share code ? How to communicate ? To create coziness in your team, you will have to rely on a great IT administrator. A magician of the command line, Powershell to setup your OS with the same configuration everywhere, yet able to update it regularly.
My recommendation is to rely on two kind of tools to produce your software : – lightweight code editors such like Atom, Visual Studio Code from Microsoft – Web IDE such like Cloud 9 or CodeEnvy is a great example. Using Eclipse Che, the web rewrite of Eclipse, a Saas IDE with the same lot of features and configuration. The most amazing thing is that this great and complex system can be installed with a Docker one liner.
As software specialists, we are well aware of the threats coming from the web applications, unobserved operating systems, data breaches. Our daily duty is to protect our customer data.
The consequence for developers is a matter of rule, our computers are locked. Software installation is double checked by IT, Internet is accessed through a proxy, antivirus, whitelist and so on. Hard disk ciphered and so on. in ch All developments have to be done on Virtual machines. BUT Virtual machines are such a pain to manage. A huge disk space, hard to customize, fairly expensive solutions (licence cost of VMWare to be able to perform VM snapshot on every developer laptop…)
Docker Datacenter
Building Virtual Disk images is a tremendous task for the system administrators : slow to copy, hard to customize, mostly manual installation and snapshots to produce them. Developers does not find the necessary flexibility to adapt to their customer projects.
Docker is offering a neat and efficient way to produce images, thanks to the docker script language. A good mix between automation and the traditional system administrator work of producing shell scripts.
Using Docker images is offering enough security control to system administrator, less efforts to maintain and developers can also provide easily their own images to the Security/Administrator Team for review. But how to store your Docker images. At the present time, I would recommend something like Docker Datacenter to host your company containers on premise.
Traditional "legacy" IT Projects features : * a code base * scripts to build the software * some manual test cases * a huge and extensive installation documentation to setup : * the test environment * the production environment * perform the maintenance, the upgrade, the backup of the system * scripts to install the database schema
In practice, most IT projects enforces developers to manually install their development, test, production environments using an out of date documentation, incomplete. How the software team is performing a QA session ? Will they create a brand new test environment with fresh data in a given state and the latest produced software version ? The answer is probably no, definitively no.
Usually, IT teams are relying on a single test server, painstakingly built through the scrum sprints, on a virtual machine. Do you think that I am exaggerating ? Ask to your team, how much time do they need to recreate this environment ? And what if their snapshot is lost or damaged ?
Continuous Dockery, ElectricCloud image property
Docker is providing several solutions to common IT project problems :
Deploying the customer application on the developer laptop : docker images are shared between developers to have access to a debug environment. Docker composer can help the software development team to build ready-to-use.
Initializing and populating a database for tests : another solution to execute integration tests is to rely on Docker to build an image, ready-to-use of your data. Start the container, wait the readiness , execute your integration tests and kill the container once used. Such scenario is easy to create with Docker, even with proprietary databases such like Oracle of MSSQL. This article is a good instruction to Docker and test automation.
Deterministic Test Automation
Recently, I have encountered a brilliant developer – although alone – maintaining a messy piece of PHP code. He was not the originator of the project, though, in charge of the project since two years. He told me that the manager offered him a virtual machine with everything on it at the begin of the project, to help him. The same one he is using on it.
Currently, he is struggling with the customer and that software. Both the customer and him have different deployment environments. And the difference of server, languages and frameworks versions is creating a huge mess.
Another project and situation. This IT team has been relying on Ansible (with Puppet it would have been the same situation), to deploy their software in the different environments. Despite the improvements thanks to the automation provided by Ansible, there is always a slight tension when launching the Ansible scripts. Maybe it’s the system entropy, the virtual machine erosion, most likely the reason is that the virtual machine has never been deleted and recreated. Anyway there are some subtile differences between the environments and probably and the Ansible deployments are sometimes failing when new features are shipped.
System erosion
With that team, we have reached a common point of view. When should we use Ansible to deploy the software ? We should rather use Ansible to prepare the virtual machines to host Docker, open the firewall, establishing the network routes, program the monitoring and so on. And the software will be shipped as a docker image, copied by Ansible and launched.
Docker/Containers can simplify your software deployments whether you have a private cloud or regular virtual machines. Simply install the docker system on your virtual machines and change your way to ship your software, past the effort, you won’t regret it.
The last situation where Docker/Containers is really brilliant is when you use Docker inside your software factory.
Docker can be used in a software factory to make your Software factory evolve from a monolithic all-usage but slow and frustrating software factory to a real platform Software Factory As A Service (If you like the term SFAAS, it’s mine 🙂
The main differences between a Software Factory and a SFAAS are the following : – Product owner, Team manager are creating the new Software Factories for their projects directly through a WebUI by picking the technologies, tools they need. – Developers have the possibility to instantiate new environments to build or test the software without any interaction, paper submission and waiting for a round trip between Earth and Mars. – Integration engineers are providing new tools and environments accessible to the projects, if they wish. – Few interactions are necessary between the infrastructure and system administration teams and the software teams. It’s a win-win solution and the IT bottleneck has been removed.
Docker Software Factory : Marcel Birkner
I strongly recommend that Software factories built on the top of containers like these great initiative projects.
If you have read the whole article, I can only say you a Big thank you and I hope you have been able to learn one thing or two. The apparition of containers is really helping developers, ops and I wish that the IT companies fully embrace these technologies to make our profession much funnier and attractive.
In 2017, this blog is powered by Hexo.js. However I am looking for a replacement since Hexo.JS is lacking of crucial features.
TLDR : HexoJS is too limited, I want online post edition!
I have been recently working to replace the technology powering my blog. A major point is that I am disappointed with its theme. I would like to replace it, with a new technology Vue.JS, for which I have already discussed there.
Since I am replacing the whole front-end, I have been using the great plugin hexo-generator-json. However I still have major issues with my assets (stored with the posts) and it is not really compatible with a CDN solution.
The second feature I am missing, is the possibility to edit my post online. I am an user of Medium and I love the mobile application to create and edits my posts as well watching statistics. A thing I did not think at first, is the impossibility to create new posts with Hexo.JS without an computer. Indeed, to generate your site, you have to generate it, using a full Node.JS environment, commiting, pushing on GITHub your modifications, deploy the docker container and so on. A lot of tasks I have mostly automated but yet, I don’t have a CI Environment available for it.
I did not want to switch back to Drupal and WordPress, equals for me as a bloated solution, slow and hard to tune. I wanted a compromise : why not having a NoSQL Database, a light REST backend, an AdminUI and that’s all. At the beginning of this blog, it was my plan to build this backend, but I decided shortly to concentrate on the content, rather than on the code.
Fortunately, the technologies have evolved and I made a list of Headless CMS / API-First CMD and tested them.
Headless CMS
I won’t spend too much time in the details, a good description has been done there.
Basically, legacy / traditional CMS are highly coupled solutions where the following components are tied :
Usually this kind of CMS are stored in one big block called WordPress, Drupal, Joomla and so on.
The good news is that even these famous solutions are evolving to apply the following modern and well-known principles :
I am expecting from an Headless CMS to contains :
The list of experiments and my opinion about it.
Docker-compose was not running (I used this project). The docker instructions worked for me.
I launched it and soon enough I received a lot of technical alerts wasting my pleasure of a fresh installation.
Directus / Error message
My last blocking point, and the reason I have rejected : I did not find any way to create a content category (called table) in the admin UI. Seems to manipulate the SQL Database to create them : no thanks (rant here).
Uh Uh, a Java solution to power a small blog : no thanks.
Too big, too well-known. The REST API is for sure the next security hole of these solutions.
But the reason of my reject, the UI cannot be separated from the backend!! And why would I like a UI embedded in my backend when I want to create a SPA WebSite ?
I will use them when they will have deleted their UI from the installer.
I suggest to call them HydraCMS.
GraphCMS
Looks Great but I want my own self-hosted solution and don’t want to pay for that.
Site here
Honestly, I had a crush with Ghost. Sexy, a great installer, a great documentation, everything to tempt me like an attractive woman.
The problem is that Ghost has almost everything to charm me but he has an embedded UI!!!
I don’t want an UI, I want to build mine 🙁
Apart from that point, GhostCMS is really great.
Ghost CMS
It even has an Slack integration and loves Markdown!!
Cockpit CMS
Listed in the Awesome CMS List, Cockpit CMS is a rather small solution.
The good points are :
** Docker is working fine. ** The concepts and architecture are OK. ** Nice AdminUI, I really appreciated the way to create my collections
But what really disappointed me was :
** No documentation (REST and so on). For an developer it’s unusable ** PHP : There is no documentation and the REST API is coded in PHP.. Meh ** Lonesome developer yes he is brave, we should encourage him, but he is freaking alone.
In summary, I think that this project goes in the right direction but took some tough and spiky path. PHP is clearly not the appropriate language for such solution. Compared to an Express server, the amount of work to be delivered is too high. It really needs more contributors (actives) to create a good solution and fill the big documentation blackhole. I cannot help since I don’t want to code again in PHP but the solution could be great.
Site is here
Well at the first glance, I rejected, could not find any Docker image. Or the few ones were not working. But my first attempt was dumb. KeystoneJS is not an Headless CMS by itself it’s rather an implementation of a CMS, fully customizable to create your own blog!
Powered by Express and Node.JS, two technologies I am particularly fond of!
The site is there
The positive sides of KeyNodeJS :
The negative points are :
I have rejected most of these solutions.
The consequence is that I am using KeystoneJS and I hope I won’t have too much work to power a new version of my blog.
Stay tune!
**
Some time ago, I organized a talk on “Code Quality and why developers should care about” for my company. In that presentation, I demonstrate some tools, unfamiliar for the audience : young developers and battle-hardened IT developers. One among these tools has brought to me a lot of questions : Codacy. I will present its features and perform a comparison between Codacy and SonarQube from SonarSource.
Recent Comments