Component :

<aura:component description="NotificationToast_cmp" access="global">
    <aura:attribute name="variant" type="String" default="success" access="global" description="gives the variant to the toast" />
    <aura:attribute name="message" type="String" default="Record Saved Successfully!" access="global" description="gives the message to the toast" />
    <aura:attribute name="duration" type="Integer" default="3000" access="global" description="gives the time duration to the toast" />
    <aura:attribute name="showToast" type="Boolean" default="false" access="global" description="to show or hide the toast" />
    <aura:handler name="change" action="{!c.changeToastHandler}" value="{!v.showToast}" />
    <aura:handler name="init" action="{!c.changeToastHandler}" value="{!this}" />

    <!--Toast Start-->
    <aura:if isTrue="{!v.showToast}" >
        <div aura:id="toast" class="slds-backdrop slds-backdrop--open" style="z-index: 10000;">
            <div class="slds-p-top_small" style="height: 4rem;">
                <div class="slds-notify_container slds-is-relative">
                    <div class="{!v.variant == 'success' ? 'slds-notify slds-notify_toast slds-theme_success':'slds-notify slds-notify_toast slds-theme_error'}" role="alert">
                        <span class="slds-assistive-text">{!v.variant}</span>
                        <span class="slds-icon_container slds-icon-utility-success slds-m-right_small slds-no-flex slds-align-top" >
                        <lightning:icon alternativeText="toast" iconName="{!v.variant == 'success'? 'utility:success' : 'utility:error'}" size="small" class="fillclr"/>
                    </span>
                        <div class="slds-notify__content">
                            <h2 class="slds-text-heading_small ">{!v.message}</h2>
                        </div>
                        <button class="slds-button slds-button_icon slds-notify__close slds-button_icon-inverse" title="Close" onclick="{!c.closeToast}" >
                            <lightning:icon alternativeText="Close" iconName="utility:close" size="small" class="fillclr"/>
                            <span class="slds-assistive-text">Close</span>
                        </button>
                    </div>
                </div>
            </div>
        </div>
    </aura:if>
</aura:component>


Controller:

({
    closeToast : function(c, e, h) {
        c.set("v.showToast", false);
    },

    changeToastHandler : function (c, e, h) {
        if (c.get('v.showToast') === true) {
            window.setTimeout(
                $A.getCallback(function () {
                    c.set("v.showToast", false);
                }), c.get('v.duration')
            );
        }
    }
})