Authentication failed for user ubuntu@{serve ip aws or other}.

in RubyOnRails ROR deployment by

cap production deploy …

If you facing this error while deployment

Steps to solve :

1 Check ssh to server ( ssh user@ip }

2 Check the you public key added in server ssh authorized keys

3. then If login is working ssh then do ,, ssh-add solved my problem



What is interpolation in angular ?

Templates always need text or string to be dynamic at runtime. So angular given us

Interpolation technique to title, username, error messages etc

We put inside {{text }} double curly braces

Class file

userName = “Anil”


Welcome, {{userName}}

Some time we need maths expression


Real Count Wins {{ total + 56 == 200 ? “Winner”: “Loser”}}

Can’t use javascript expression

+= , new , instanceof , typeof , ;

Angular runs template expressions after every change detection cycle runs.



Component is an element of the Angular app. They are the main building blocks. Each component is a type of directive. Component is made of class with Component metadata, html template, css selector and optionally css style apply to html template. Component have lifecycle hooks.

Cli command

ng g c app-component-overview

Syntax :-


selector: ‘app-component-overview’,

templateUrl: ‘./component-overview.component.html’,

styleUrls: [‘./component-overview.component.css’]


export class ComponentOverviewComponent {






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