We're currently using RightScale, and every time we deploy, we execute a script on the server or server array that we want to update. It pulls the code from a GitHub repository, creates a new folder in /var/www/releases/TIMESTAMP, and symlinks the document root, /var/www/current, to that directory.
We're looking to get a better deployment strategy, such as something where we SSH into one of the servers on the private network, and run a command-line script to deploy what we want to deploy.
However, this means that this one server has to have its public key in the authorized_keys of all of the servers we want to deploy to. Is this safe? Wouldn't this be a single server that would allow all the other servers to be accessed?
What's the best way to approach this?
Thanks!
We use a similar strategy to deploy, though we're not with Rightscale anymore.
I think generally that approach is fine and I'd be interested to learn what you think is not serious about it.
If you want to do your ssh thing, then I'd go about it the following:
Lock down ssh using security groups, e.g. open ssh only up to specific IP or servers with a deploy security-group, or similar. The disadvantage here is that you might lock yourself out when the other servers are down, etc..
I'd put public keys on each instance to allow a password-less login. If you're security concious, you rotate those keys on a monthly basis or for example, when employees are leaving, etc..
Use fabric or capistrano to log into your servers (from the deploy master) using ssh and do your deployment.
Again, I think Rightscale's approach is not unique to them. A lot of services do it like that. The reason is that e.g. when you symlink and keep the previous version around, it's easier to rollback and so on.
Related
I am the only developer (full-stack) in my company I have too much work other than automating the deployments as of now. In the future, we may hire a DevOps guy for the same.
Problem: We have 3 servers under Load Balancer. I don't want to block 2nd & 3rd servers till the 1st server updated and repeat the same with 2nd & 3rd because there might be huge traffic for one server initially and may fail at some specif time before other servers go live.
Server 1
User's ----> Load Balancer ----> Server 2 -----> Database
Server 3
Personal Opinion: Is there a way where we can pull the code by writing any scripts in the Load Balancer. I can replace the traditional Digital Ocean load balancer with Nginx Server making it a reverse proxy.
NOTE: I know there are plenty of other questions asked in Stack
Overflow on the same but none of them solves my queries.
Solutions I know
GIT Hooks - I know somewhat about GIT Hooks but don't want to use it because if I commit to master branch by mistake then it must not get sync to my production and create havoc in the live server and live users.
Open multiple tabs of servers and do it manually (Current Scenario). Believe me its pain in the ass :)
Any suggestions or redirects to the solutions will be really helpful for me. Thanks in advance.
One of the solutions is to write ansible playbook for this. With Ansible, you can specify to run it per one host at the time and also as the last step you can include verification check that checks if your application responds with response code 200 or it can query some endpoint that indicates the status of your application. If the check fails, Ansible will stop the execution. For example, in your case, Server1 deploys fine, but on server2 it fails. The playbook will stop and you will have servers 1 and 3 running.
I have done it myself. Works fine in environments without continuous deployments.
Here is one example
I want to use Postgresql in Windows Server 2012 R2 for one our project where it can be 24/7 uptime.
I would like to ask the community if I can have 2 master instances in 2 different servers A&B and they will 'work' on the same DB located in a shared file storage in lan. Always one master instance on server A will be online and when it goes offline for some reason (I suppose) a powershell script will recognize that the postgresql service stopped and will start the service in server B. The same script will continuous check that only one service in servers A & B is working to avoid conflicts.
I'd like to ask if this is possible or a better approach for my configuration.
(I can't use replication because when server A shuts down the server B is in read-only mode thing that I don't want)
If you manage to start two instances of PostgreSQL on the same data directory, serious data corruption will happen.
Normally there is a postmaster.pid file that prevents that, but a PostgreSQL server process on a different machine that accesses the same file system will happily unlink that after spewing some log messages, thinking it was left behind from a crash.
So you are really walking on thin ice with a solution like that.
One other issue that you didn't think of is that script that is supposed to check if the server is still running. What if that script fails, because for example the network connection between the two servers is down, but the server is still up an running happily? Such a “split brain” scenario will cause data corruption with your setup.
Another word of caution: since you seem to be using Windows (Powershell?), you probably envision a CIFS file system when you are talking of shared storage. A Windows “network share” is not a reliable file system — last time I checked, it did not honor _commit.
Creating a reliable failover cluster is harder than you think, and I'd recommend that you check existing solutions before you try to roll your own.
I've read some articles recently on setting up AWS infrastructure w/o enabling SSH on Ec2 instances. My web app requires a binary to run. So how can I deploy my application to an ec2 instance w/o using ssh?
This was the article in question.
http://wblinks.com/notes/aws-tips-i-wish-id-known-before-i-started/
Although doable, like the article says, it requires to think about servers as ephemeral servers. A good example of this is web services that scale up and down depending on demand. If something goes wrong with one of the servers you can just terminate your server and spin up another one.
Generally, you can accomplish this using a pull model. For example at bootup pull your code from a git/mecurial repository and then execute scripts to setup your instance. The script will setup all the monitoring required to determine whether your server and application are up and running appropriately. You would still need an SSH client for this if you want to pull your code using ssh. (Although you could also do it through HTTPS)
You can also use configuration management tools that don't use ssh at all like Puppet or Chef. Essentially your node/server will pull all your application and server configuration from the Puppet master or the Chef server. The Puppet agent or Chef client would then perform all the configuration/deployment/monitoring changes for your application to run.
If you with this model I think one of the most critical components is monitoring. You need to know at all times if there's something wrong with one of your server and in the event something goes wrong discard the server and spin up a new one. (Even better if this whole process is automated)
Hope this helps.
I've deployed in Windows Azure a website made with Umbraco, using
Windows Azure Accelerator for Umbraco.
For development and test i used a test Hostname. Now it's time to switch to the official DNS hostname..
How can I change current hostname?
Actually i configured hostname at deployment time (the only way i know to do this) but i can't deploy again, since many files have been changed working on website on Azure.
EDIT
Let me explain: at the step prompt in the image (during web site deploying) I used as Domain Name "test.mywebsite.com", and configured real DNS.
Now the website is configured, so I'd like to make mywebsite.com point to that site;
But is'nt enough if i configure mywebsite DNS! Shall I deploy again? An will I lose any of the changes I made?
I'd like to make two comments on your question:
1) In order to host your Azure application under a custom host name, you will need to sign up with a DNS provider that supports C-NAME records (most do). I suggest someone like GoDaddy.com because by default C-NAME records can only resolve your "www.domainname.com" records and cannot do anything for queries where "www." is dropped from the URL. DNS providers like GoDaddy also have an option to redirect all traffic destined for "domainname.com" to a URL of your choice. This is a huge deal for Azure apps. Frankly speaking, it is somewhat disappointing that for all the PaaS and IaaS features of Azure, DNS was not included in the overall package.
2) I am a little worried when you say that you can no longer redeploy your app due to the changes made. Can you elaborate on that? Have you made changes to the application's code running on VM's in Azure without going through redeployment process? If so, this is a huge no-no. Your VM's running in Azure are not "permanent". Microsoft and your redeployment process can (and will) re-stage those VM's to the original package at any given time. Microsoft will re-image your VM's at least once a month during their monthly OS upgrades. But they can also do so when they need to move your VM to another rack, etc. Whatever changes that you make to your app must be either stored in source-control before deployment or in a permanent storage facility like SQL Azure, Azure Storage, etc.
HTH
Finally i think that the answers to my questions are:
-Shall I deploy again? Yes, i must deploy again
-Will I lose any of the changes I made? Many changes will be mantained since are stored into DB. But I have to do many activities to make new website work!
This answer confirms my theory:
In my case, I created and uploaded a site with a name, let's say
http://www.contoso.com and then paid a domain from a registrar let's say
http://www.example.com, when I mapped
http://MyAcceleratorsService.cloudapp.net/ to my new domain
( http://www.example.com ) and tried to open that domain I got the home page of
the Accelerator and not the uploaded site.
I had to upload the site again to Azure (using UploadUmbracoSite.cmd
from Accelerator application) and when uploading enter the same domain
name as the one I registered: http://www.example.com. Then, I was able to
browse my uploaded site as expected.
As for your question, will upload site again using
UploadUmbracoSite.cmd (is in the Setup folder) and will enter the new
domain name when requested.
Exactly what I was trying to avoid.. but the only solution, i suppose.
Well it was not easy to publish again, i got errors of many type (i suppose tied to some components that i've installed after deploy and that are not installed in new deployed website).. i'm going to solve them.
Edit
Completed my work:
- loads of different attempts, no-one worked
- CTP backup of DB
- deleted DB and website
- new full deploy of umbraco
- CTP restore of DB
finally:
-all work on content is OK
-all work on styles, pages, templates is lost
Changing hostname is hard; dont'use test hostname but definitive hostname from the beginning.
If anyone has suggest, i'll be pleased to test it, anyway
This is not really an answer to your question, but it might be a solution to your problem: Use a CNAME record to make the production DNS name point to your development name. E.g. www.productionname.com will the point to www.testname.com. I am not sure if everything will just work out of the box, but it seems to be worth a try.
This requires, that your hosting provider allows you to set up CNAME records.
http://en.wikipedia.org/wiki/CNAME_record
We use Windows Azure Cloud services to host our application. One of the great features of Windows Azure is the Production/Staging model. You can have the clients of your application routed to your production server, while you can test your new code running on a staging server. For example, you can configure Azure to point a production server to http://www.coolapp.com while designating a staging server for the same app to something like this: http://7f8e9d5ba73a4f7ea9ebd65a02ee195d.cloudapp.net.
Physically both of these servers are publicly facing. If you were to know the cryptic URL of a staging server you would be able to browse to the app just as easily as you would browse to www.coolapp.com. However, the presence of a GUID in the URL makes it virtually impossible for someone to guess it, thus making the staging server "private". This gives a nice mechanism to the developers of an application to deploy and test the new bits on a staging server before releasing them to public. Once they make sure that things look good, with a flip of a switch they swap the two servers, making staging server a production server and vice versa.
This model creates a small problem for us in relation to Facebook integration. To be able to integrate Facebook plugins you have to register your app with them. FB will then issue an AppId and an AppSecret keys. These keys are tied to the URL of your application. So in order for my app to work with FB plugins I need to obtain one set of keys that is tied to 7f8e9d5ba73a4f7ea9ebd65a02ee195d.cloudapp.net, and another set that is tied to www.coolapp.com.
When I read about Windows Azure, they really urge developers to treat staging vs. production servers as the same. The only difference between them should be the URL. In other words, Azure does not recommend basing your app logic on which server the code happens to be running on as Azure has no inherent knowledge of this. Staging vs. production is just a handy "abstraction" if you will. I guess you see the problem here. In our example above, I have to use one set of keys issued by FB versus another depending on which URL (production vs. staging) my app is running at. I assume I am not the first one running into this problem. What are the correct ways of handling this? One obvious way is to sniff the URL property of the Request object and branch my logic that way. However, intuition tells me this is a hack. Any other ideas?
Regards,
Archil
The mechanisms I know of are:
using "production" within a totally separate service account to "testing" - this leaves "staging" within the production service to be used as an area for "deployment candidates" and provides a separate clean testing domain with a non-changing URL for earlier "dev and test" work.
using different .cscfg files for staging and production - and being careful to update this .cscfg before you do any live switching.
sniffing the incoming URL - as you suggest
Personally, I use the first of these techniques - its easy and it helps prevent nasty accidents
As an aside, one of the techniques we've used for "removing" the Guid from staging is to CNAME the Guid with a really short TTL on the DNS - this allows us to quickly and automatically update the CNAME record for the staging server when we deploy.