I've been studying "Kubernetes Up and Running" by Hightower et al (first edition) Chapter 13 where they discussed creating a Reliable MySQL Singleton (Since I just discovered that there is a second edition, I guess I'll be buying it soon).
Using their MySQL reliable singleton example as a model, I've been looking for some sample YAML files to make a similar deployment with Microsoft SQL Server (Express) on Docker Desktop for Kubernetes.
Apparently I need YAML files to deploy
Persistent Volume
Volume claim (should this be NFS?)
SQL Server (Express edition) replica set (in spite of the fact that this is just a singleton).
I've tried this example but I'm confused because it does not contain a persistent volume & claim and it does not work. I get the error
Error: unable to recognize "sqlserver.yml": no matches for kind "Deployment" in version "apps/v1beta1"
Can someone please point me to some sample YAML files that are not Azure specific that will work on Docker Desktop Kubernetes for Windows 10? After debugging my application, I'll want to deploy this to Azure (AKS).
Wed Jul 15 2020 Update
I left out the "-n namespace" for the helm install command (possibly because I'm using Helm and you are using helm v2?).
That install command still did not work. Then I did a
helm repo add stable https://kubernetes-charts.storage.googleapis.com/
Now this command works:
helm install todo-app-database stable/mssql-linux
Progress!
When I do a "k get pods" I see that my todo-app-mssql-linux database is in the pending state. So I did a
kubectl get events
and I see
Warning FailedScheduling pod/todo-app-database-mssql-linux-8668d9b88c-lsh5l 0/1 nodes are available: 1 Insufficient memory.
I've been google searching for "Kubernetes insufficient memory" and can find no match.
I suspect this is a problem specific to "Docker Desktop Kubernetes".
When I look at the output for
helm -n ns-todolistdemo template todo-app-database stable/mssql-linux
I see the deployment is asking for 2Gi. (Interesting: when I use the template command, the "-n ns-todolistdemo" does not cause an error like it does with the install command).
So I do
kubectl describe deployment todo-app-database-mssql-linux >todo-app-database-mssql-linux.yaml
I edit the yaml file to change 2Gi to 1Gi.
kubectl apply -f todo-app-database-mssql-linux.yaml
I get this error:
error: error parsing todo-app-database-mssql-linux.yaml: error converting YAML to JSON: yaml: line 9: mapping values are not allowed in this context
Hmm... that did not work. I try delete:
kubectl delete deployment todo-app-database-mssql-linux
kubectl create -f todo-app-database-mssql-linux.yaml
I get this error:
error: error validating "todo-app-database-mssql-linux.yaml": error validating data: invalid object to validate; if you choose to ignore these errors, turn validation off with --validate=false
So I try apply:
kubectl apply -f todo-app-database-mssql-linux.yaml
Same error!
Shucks.... Is there a way to adjust the memory allocation for Docker Desktop?
Thank you
Siegfried
Short answer
https://github.com/helm/charts/blob/master/stable/mssql-linux/templates/pvc-master.yaml
Detailed Answer
Docker For Desktop comes already with a default StorageClass :
This storage class is responsible for auto-provisioning of PV whenever you create a PVC.
If you have a YAML definition of PVC (persistent volume claim), you just need to keep storageClass empty, so it will use the default.
k get storageclass
NAME PROVISIONER AGE
hostpath (default) docker.io/hostpath 11d
This is fair enough as Docker-For-Desktop Cluster is a one node cluster. So if your DB crashes and the cluster opens it again , it will not move to another node, because simply, you have a single node :)
Now should write the YAML of PVC from scratch ?
No , you don't need. Because Helm should be your best friend.
( I explained below Why you have to use Helm even without deep learning curve)
Fortunately, the community provides a chart called stable/mssql-linux..
Let's run it together :
helm -n <your-namespace> install todo-app-database stable/mssql-linux
# helm -n <namespace> install <release-name> <chart-name-from-community>
If you want to check the YAML (namely PVC) that Helm computed, you can run template instead of install
helm -n <your-namespace> template todo-app-database stable/mssql-linux
Why I give you the answer with Helm ?
Writing YAML from scratch lets reinventing the wheel while others do it.
The most efficient way is to reuse what community prepare for you.
However, you may ask: How can i reuse what others doing ?
That's why Helm comes.
Helm comes to be your installer of any application on top of kubernetes regardless how much YAML does your app require.
Install it now and hit the ground choco install kubernetes-helm
Related
I would like to install, configure, deploy and serve a local react application using Ansible but i cannot get any valuable information to do it.
Is there anybody who can guide me on how to achieve this?
Thanks in advance.
First off, ansible has a REALLY extensive wiki here. That will show you the many modules that can be used to do specific tasks. However, this is not where I would start for writing your first playbook, it gets rather daunting.
However, I started and would recommend you start on this tutorial on how to make your first playbook. you would make a yaml file and run it using the 'ansible-playbook' command on a host that has ssh enabled, ansible installed, and a key pair setup (easily done with ssh-copy-id user#hostname). If you need a way to quickly provision these machines, I personally use Hashicorp's Vagrant to quickly make simple Virtual Machines, however it is possible to use Docker or something else.
As for the specifics for installing specific applications using apt; use the apt module in ansible should serve you right. If you need to install NPM or something of the sort, chances are there's a module for that too. As for copying configs you would want the copy module. Things are pretty straight forward. a good way to structure the google searches to find specific modules would be something like "ansible copy files" and find something from docs.ansible
I realize that this is rather vague; however, I'm not completely sure on your use case in this scenario simply because of the broadness of the question.
Thanks a lot for your input, it was very helpful.
I finally achieved what i was looking for, and for reference here's how i made it. Hope this is useful for other users.
Assuming you have already installed Ansible in your machine, the following should do the job.
vim inventory
[appserver]
127.0.0.1 ansible_connection=local
vim playbook.yml
---
- hosts: appserver
tasks:
- name: Installing nodejs
apt: name=nodejs update_cache=yes
- name: Installing npm
apt: name=npm update_cache=yes
- name: Installing dependencies
command: npm install
- name: Building
command: npm run build
- name: Installing web server
command: npm install serve
- name: Running app on http://localhost:8080
command: chdir=./build serve -p 8080
To run it, just place the following in your CLI
sudo ansible-playbook -i inventory playbook.yml
I followed the official doc for deploying DataPusher to a production environment (https://docs.ckan.org/projects/datapusher/en/latest/deployment.html) but am getting OperationalError: (sqlite3.OperationalError) attempt to write a readonly database [SQL: u'INSERT INTO jobs...
I recognize this error is more to do with SQLAlchemy, namely the apache2 www-user user does not have permission to write to the SQLite database that the wsgi DataPusher app uses to keep track of jobs. I have limited experience with wsgi apps so I'm not really sure where to start with debugging...
I followed the official documentation to a T, however it's worth noting that I am replacing this with what was a functioning DataPusher development installation on the same server. I believe I have removed everything related to the development install.
Also worth noting is that /usr/lib/ckan/default points to /home/ubuntu/ckan/lib/default for an inexplicable reason. Also I believe this was a source install rather than a package install (hence my needing to deploy DataPusher).
I have tried adapting the documentation for the ckan directory being in /home/ubuntu, however I don't think this should matter since /usr/lib/ckan/default still points to the same effective location.
You'll need to chmod 777 (or the like) the sqlite (.db) file that is specified in the /etc/ckan/datapusher_settings.py file.
For example, the datapusher_settings.py file has the line for SQLALCHEMY_DATABASE_URI that points to /tmp/job_store.db by default.
So sudo chmod 777 /tmp/job_store.db. I don't think it's much a concern to 777 this particular file, but it's likely a less-open value will suffice (e.g. 655). It may be best to chown to apache since that is the only thing that should be accessing this sqlite file, much less editing it.
No issues from ckan being installed in a non-standard directory (in this case, since /usr/lib/ckan/default still directs to the ckan directory).
I've been holding off posting here because I feel like this issue could be too vague. I will try my best to explain. I have been through all of the existing questions but they don't seem relevant to what I am doing.
Basically, I have inherited 3 Ec2 Instances that are Dev / Staging / Live web applications in my new role. I use Ansible playbooks to migrate the Database between all environments. We recently had a new website that was deployed onto all three existing instances.
The Dev box recently died so I blew it away and launched a new one, the website looks fine, however exporting and importing the Database no longer works (on the new instance)
Below is the Ansible output:
TASK: [Export database to migrate] ********************************************
failed: [172.**.**.***] => {"changed": true, "cmd": "wp db export dbv2.sql --tables=t*******0_links,t*******0_options,t*******0_postmeta,t*******0_posts,taxlt4ws0_rg_form,taxlt4ws0_rg_form_meta,taxlt4ws0_rg_form_view,t*******0_term_relationships,t*******0_term_taxonomy,t*******0_termmeta,t*******0_terms,t*******0_usermeta,t*******0_users", "delta": "0:00:00.001594", "end": "2017-09-01 10:21:25.225355", "rc": 127, "start": "2017-09-01 10:21:25.223761", "warnings": []}
stderr: /bin/sh: 1: wp: not found
FATAL: all hosts have already failed -- aborting
Things I've checked:
Chmod on the folders it import/exports in/from.
IAM Role is set
Used Shell instead of Command in the Playbook
Configs for each environment
I'm really stumped my Ansible knowledge is quite limited as I only picked it up a couple months ago and hadn't run into any issues (even with a new Website) until the Dev box had to be replaced.
I think ansible is referring to wpcli. It is not able to find its executable.
If this is the case,you need to install it with another task before that one.
Basically what this is complaining about is that whatever script you are using in module Export DB is not able to find a wp script or executable.
stderr: /bin/sh: 1: wp: not found
Would recommend checking which wp or maybe do a find to see if it is on the staging or live instances to see what it is and install/copy it over to the Dev instances.
You can test this hypothesis by using a small test script:
#!/bin/sh
wp
create this script say test.sh, give it executable permissions and run it on all the env's to see where it fails.
Currently the GAE Managed VMs feature is broken for any project with a name longer than 27 characters.
The underlying issue is that Docker restricts image namespace to between 4-30 chars. This has been fixed (https://github.com/docker/docker/issues/10392) but is still awaiting a release at time of writing.
It seems when deploying a Managed VM to GAE that the namespace is automatically generated from your project name plus _m_ prefix. This leads to error when attempting to deploy the vm:
DEBUG: "POST /v1.10/images/gcr.io/_m_<my project name>/<my project name>.default.20150330t140211/push HTTP/1.1" 500 111
INFO: Exception 500 Server Error: Internal Server Error ("Invalid namespace name (_m_<my project name>). Cannot be fewer than 4 or more than 30 characters.") thrown in ProgressHandler. Retrying.
The obvious solution would be for GAE gcloud tools to respect the underlying limit via some auto-truncation or hashing scheme.
Does anyone know a way around this? Or I have to wait for Google to fix or Docker to release a new version and Google to update?
We're aware of the issue and we're working on a long-term fix. For now, you can switch to an old version of gcloud. You can do this by setting this variable to point to an old version (0.9.51):
gcloud config set --scope=installation component_manager/fixed_sdk_version 0.9.51
then run "gcloud components update"
Then run "gcloud config set app/hosted_registry false"
and you should be able to deploy. I'll update this answer when we've fixed the naming issue.
UPDATE:
The naming issue has been fixed as of this week's release (0.9.57).
I have GWT app, which is deployed on GAE (Java). I'm trying to download data from App Engine datastore using appcfg.py . I did all the setup according to http://ikaisays.com/2010/06/10/using-the-bulkloader-with-java-app-engine/ .
GAE Python SDK version is 1.4.3
Python version is 2.5.4
appcfg.py is on my PATH. When I run appcfg.py on the command-line, I get the "help" message. But the problem is that no matter which command I use, it always returns the help message. I have not been able to run any command using appcfg.py.
It doesn't give any specific error message no matter what arguments I give. My app is using Google Accounts authentication, but I don't think it even gets to the point of authentication.
I'm able to use the Java appcfg (for other actions like rollback) without any problem. But the Python version simply refuses to work for all commands.
I've tried different formats like:
appcfg.py create_bulkloader_config --url=http://myappid.appspot.com/remote_api --application=myappid --filename=config.yml
appcfg.py create_bulkloader_config --filename=bulkloader.yaml --url=http://myappid.appspot.com/remote_api
appcfg.py --filename=bulkloader.yaml --url=http://myappid.appspot.com/remote_api create_bulkloader_config
All give me the same help message:
Usage: appcfg.py [options]
Action must be one of:
create_bulkloader_config: Create a bulkloader.yaml from a running application.
cron_info: Display information about cron jobs.
download_app: Download a previously-uploaded app.
download_data: Download entities from datastore.
help: Print help for a specific action.
request_logs: Write request logs in Apache common log format.
rollback: Rollback an in-progress update.
set_default_version: Set the default (serving) version.
update: Create or update an app version.
update_cron: Update application cron definitions.
update_dos: Update application dos definitions.
update_indexes: Update application indexes.
update_queues: Update application task queue definitions.
upload_data: Upload data records to datastore.
vacuum_indexes: Delete unused indexes from application.
Use 'help <action>' for a detailed description.
Options:
-h, --help Show the help message and exit.
-q, --quiet Print errors only.
-v, --verbose Print info level logs.
--noisy Print all logs.
-s SERVER, --server=SERVER
...
...
...
Even when I try "appcfg.py help create_bulkloader_config" for a detailed description, it still shows me the same standard help.
I have also tried on the local development server using the url http://127.0.0.1:8888/remote_api but it still gives the same help message.
I'm totally clueless as to what the problem is. I'm new to GWT and GAE, and any help will be appreciated.
Thanks.
The following fix worked for me. It looks like appcfg.py doesn't like PYTHON27 and ALWAYS returns the help menu. I fixed it by executing it with PYTHON25 and hard coded all my file locations:
C:\Python25-archive\python "C:\Program Files (x86)\Google\google_appengine\appcfg.py" rollback C:\scripts\myapp
The right way is to change the environment variables on Windows 7:
Go to System Properties
Go to Advance System Settings
Click on Environment Variables
Append to Path variable the values C:\Python27\
Click Ok and restart your computer. (Yes, it is needed.)
Another way is to:
Open command Prompt
Locate your python.exe file. For example:
C:\Python27>_
Then, run a python command that looks like this.
python <appcfg_directory> download_app -A <your_app_id> -V <your_app_version> <output-dir>
Where <appcfg_directory> is equal to C:\Program Files\Google\google_appengine\appcfg.py. (Depending on your file location)
Don't forget to put quotes before and after <appcfg_directory>