private void logFailure(Session session, FileReference fileReference, ApplicationId applicationId) {
        var deployed = Instant.ofEpochMilli(session.getMetaData().getDeployTimestamp());
        var level = Duration.between(deployed, applicationRepository.clock().instant()).toMinutes() > 2
                ? INFO
                : FINE;
        log.log(level, "Downloading application package (" + fileReference + ")" +
                " for " + applicationId + " (session " + session.getSessionId() + ") unsuccessful.");
    }
Verifies that all active sessions has an application package on local disk.
If not, the package is downloaded with file distribution. This can happen e.g.
if a config server is down when the application is deployed. This maintainer should only be run
if there is more than 1 config server

@author gjoranv
configserver/src/main/java/com/yahoo/vespa/config/server/maintenance/ApplicationPackageMaintainer.java